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1
Pham, D. K. G., P. Desgreys, P. Loumeau e T. Ridgers. "Multi-stage noise band cancellation modulator for digitisation of distorted signals". Electronics Letters 48, n. 10 (2012): 560. http://dx.doi.org/10.1049/el.2012.0533.
2
HUSSAIN, AMIR. "MULTI-SENSOR NEURAL-NETWORK PROCESSING OF NOISY SPEECH". International Journal of Neural Systems 09, n. 05 (ottobre 1999): 467–71. http://dx.doi.org/10.1142/s0129065799000496.
Abstract (sommario):
In this paper, a novel Artificial Neural-Network (ANN) based multi-sensor multi-band adaptive signal-processing scheme is described for enhancing acoustic-speech corrupted by real noise and reverberation. Numerically robust adaptation-algorithms are employed for the ANN based sub-band filters; and, new simulation experiments are reported using real-reverberant automobile data which demonstrate that the proposed speech-enhancement system is capable of outperforming conventional linear filtering-based wide-band and multi-band noise-cancellation schemes.
3
Seethur, Rashmi, Siva Yellampalli e Shreedhar H. K. "Design of Common Gate Current-Reuse Noise Cancellation UWB Low Noise Amplifier in 90nm CMOS". International Journal of Electronics, Communications, and Measurement Engineering 11, n. 1 (1 gennaio 2022): 1–14. http://dx.doi.org/10.4018/ijecme.312257.
Abstract (sommario):
In this paper, an ultra-wide band (UWB) low noise amplifier (LNA) is implemented by using 90nm RF CMOS technology. The designed LNA achieves high flat band gain (S21) and low noise figure (NF) in the frequency of interest. The proposed LNA operates in the frequency range of 3GHz to 8GHz. In this work, wide band matching is achieved by designing common gate configuration at the input stage. The current reuse and noise cancellation techniques are introduced to improve flat band gain and minimize both noise figure and power consumption. The noise figure is improved by cancelling dominant noise sources with additional hardware. The proposed LNA attains flat band gain of 26.5dB and input matching less than -12dB for entire UWB band. This work achieves noise figure of 2.1dB to 2.59dB in frequency band of interest. Additionally, power consumption of the circuit is 20mW at 1.8V supply voltage.
4
Zhu, Hong Yu, Chao Wang, Nai Chang Yuan, Jing Jian Huang e Qing Ping Wang. "Multi-domain blind source separation in-band full-duplex technique considering RF impairments". Journal of Physics: Conference Series 2625, n. 1 (1 ottobre 2023): 012060. http://dx.doi.org/10.1088/1742-6596/2625/1/012060.
Abstract (sommario):
Abstract In-band full-duplex (IBFD) technology can potentially improve spectrum efficiency compared to half-duplex technology. The cancellation of the self-interference (SI) signal is the key to implementing the IBFD system to achieve accurate detection of the signal of interest. In this work, we fully account for the effect of IQ imbalance, phase noise (PN), additional Gaussian white noise (AWGN), and the nonlinear caused by the RF impairments of power amplifier, and adopt the method of canceling SI signal combined with the propagation, analog, and digital domain to cancel the SI signal, but the residual SI signal is still mixed with the signal of interest in the same time and frequency domain. In addition, a novel multi-domain blind source separation (MDBSS) self-interference cancellation method implemented by using the off-the-shelf components is proposed in this paper, which can realize the separation of residual self-interference signals from the signal of interest (SOI). Additionally, the multi-domain blind source separation (MDBSS) self-interference cancellation technique is used to achieve 75 dB of self-interference cancellation performance, which is proven through numerical simulation analysis, and the SOI is successfully separated in the receiver. Moreover, the multi-domain blind source separation (MDBSS) method in this paper can be applied to radar, jammer, and communication systems in the future.
5
Hwang, Yuh-Shyan, San-Fu Wang e Jiann-Jong Chen. "A differential multi-band CMOS low noise amplifier with noise cancellation and interference rejection". AEU - International Journal of Electronics and Communications 64, n. 10 (ottobre 2010): 897–903. http://dx.doi.org/10.1016/j.aeue.2009.07.003.
6
Pham, Dang-Kièn Germain, Patricia Desgreys, Patrick Loumeau, Tim Ridgers e Guillaume Monnerie. "High-level design of general multi-stage noise band cancellation $$\Upsigma\Updelta$$ Σ Δ ADC optimized for nonlinearly distorted signals". Analog Integrated Circuits and Signal Processing 77, n. 2 (28 settembre 2013): 235–45. http://dx.doi.org/10.1007/s10470-013-0148-1.
7
Kim, Hyoung Soo, Sungho Beck, Kwanyeob Chae, Kyutae Lim, Joy Laskar e Manos M. Tentzeris. "A Frequency Selective Feedback Receiver for Multi‐Bands Operation". Microwave and Optical Technology Letters 60, n. 10 (26 settembre 2018): 2584–94. http://dx.doi.org/10.1002/mop.31401.
Abstract (sommario):
AbstractFor a frequency‐division duplex (FDD) wide‐band code‐division multiple‐access (WCDMA) system, transmit (TX) signal leakage at the receiver input degrades the receiver performance. To cancel this TX leakage, a frequency selective feedback was previously proposed, but it had an unpredictable feedback loop characteristic due to the uncertainty of the duplexer impedance. This paper presents a new method to achieve TX leakage cancellation regardless of the duplexer impedance. In addition, a local oscillator (LO) phase shift technique is proposed to apply this method for multi‐band. A receiver adopting these proposed techniques is implemented using a 0.18‐μm CMOS process to prove the concept. The measured TX attenuations of the high‐ and low‐band are 17‐dB and 20‐dB, respectively, and the measured noise Figure (NF) degradations of the high‐ and low‐band are 0.6‐dB and 0.5‐dB, respectively. The measurement results demonstrate effectiveness of the proposed techniques.
8
A. Naman, Hala, e A. E. Abdelkareem. "Communication Channel Influence on Self Interference Cancellation for In-Band Full-Duplex Underwater Acoustic Systems". Iraqi Journal of Information and Communication Technology 6, n. 2 (31 agosto 2023): 1–16. http://dx.doi.org/10.31987/ijict.6.2.210.
Abstract (sommario):
This paper employs a self-interference cancellation (IBFD-UWA) system for shallow-water acoustic channels by depending on the model of communication channel for SI cancellation, which is based on geometry to accommodate any possible changes in the underwater environment. UWA channels have propagation characteristics based on the configurations of straight and multi-direction mirrors between a transmitter and a receiver. This propagation at the node itself and between the two nodes to transfer information between the nodes operating in the IBFD mode, orthogonal frequency division multiplex (OFDM) modulation with quadrature phase-shift keying (QPSK) mapping. By using numerical simulations, it can be shown that the developed model is able to accurately describe the underwater acoustic environment. The results indicate that local multipath propagation delays can exceed 1.4s with transmission losses of up to 80dB, and the SIC requires about 4 seconds to reduce SI signals to background noise levels successfully.
9
Chen, Xin Han, Shuxiang Song e Mingcan Cen. "Design and Analysis of a Broadband Current-Mode CMOS Direct-Conversion Receiver Frond-End Circuit". Journal of Circuits, Systems and Computers 28, n. 10 (settembre 2019): 1950169. http://dx.doi.org/10.1142/s021812661950169x.
Abstract (sommario):
A broadband (0.8–5[Formula: see text]GHz) CMOS current-mode direct-conversion receiver has been integrated in a 0.18-[Formula: see text]m CMOS process. The proposed receiver front-end features a broadband active-balun low-noise transconductance amplifier (LNTA) driving a current-mode passive mixer terminated by a low-input-impedance transimpedance amplifier (TIA). The receiver chain has improved robustness to out-of-band interference, conversion gain and outstanding linearity. With the technique of noise and distortion cancellation which performs a better input impedance matching, we employ a broadband common-gate–common-source (CG–CS) LNTA and a current mirror to improve both gain and noise figure (NF) performance. Compared to the 50% duty-cycle switching stage, the 25% duty-cycle I–Q switching stage is implemented by using serial switches driven by 50% quadrature local oscillator (LO) signals separately, which improves the down-conversion gain by 3[Formula: see text]dB and lowers the noise figure. The transimpedance amplifier employs the [Formula: see text]-boosting technique to realize low input impedance and high transimpedance gain. The core circuit (RF and baseband signal path) consumes 26[Formula: see text]mW, and the prototype receiver achieves approximately 33–34.5-dB conversion gain, 8.1–9.35-dB NF and 7.5–9.8-dBm IIP3 from 0.8[Formula: see text]GHz to 5[Formula: see text]GHz.
10
Luo, Kai, Zhongliang Deng, Xiaobin Guo, Ziyao Ma e Jingrong Liu. "High-Precision Ranging Method of 5G NR Co-Band PRS in Industrial Internet Scenarios". Applied Sciences 13, n. 18 (14 settembre 2023): 10302. http://dx.doi.org/10.3390/app131810302.
Abstract (sommario):
To meet the demand for high-precision positioning in commercial industrial internet scenarios, 3GPP introduced the Positioning Reference Signal (PRS) in the 5G standard. However, the PRS signal occupies specific time and frequency resources for transmission in 5G systems, limiting the efficiency of communication signal transmission to some extent. In this regard, we propose a 5G NR Co-Band PRS model that allows for the superimposition of PRS signals on communication signals in a low-power manner, without requiring additional communication resources or causing too much interference to the communication signal. Since orthogonal frequency division multiplexing (OFDM) signals are sensitive to synchronization errors, we have developed a three-stage Co-Band PRS-based reception scheme. First, an innovative weighted window coarse synchronization method is proposed to enhance the performance of capturing communication signals at a low signal-to-noise ratio (SNR). Next, the interference cancellation technique is utilized to remove the communication signals, and the synchronization error is corrected through multipath delay estimation. Finally, to further improve the ranging accuracy, we propose an iterative delay-locked loop (DLL) algorithm that can achieve a tracking accuracy of one percent sampling. Simulation and real environment tests confirm that the proposed Co-Band PRS reception scheme can achieve a ranging accuracy of 0.16 m@90%.
11
Ko, Goo-Han, Seung-Jin Moon, Seong-Hoon Kim, Jeong-Geun Kim e Donghyun Baek. "Fully Integrated 24-GHz 1TX-2RX Transceiver for Compact FMCW Radar Applications". Sensors 24, n. 5 (23 febbraio 2024): 1460. http://dx.doi.org/10.3390/s24051460.
Abstract (sommario):
A fully integrated 24-GHz radar transceiver with one transmitter (TX) and two receivers (RXs) for compact frequency modulated continuous wave (FMCW) radar applications is here presented. The FMCW synthesizer was realized using a fractional-N phase-locked loop (PLL) and programmable chirp generator, which are completely integrated in the proposed transceiver. The measured output phase noise of the synthesizer is −80 dBc/Hz at 100 kHz offset. The TX consists of a three-bit bridged t-type attenuator for gain control, a two-stage drive amplifier (DA) and a one-stage power amplifier (PA). The TX chain provides an output power of 13 dBm while achieving <0.5 dB output power variation within the range of 24 to 24.25 GHz. The RX with a direct conversion I-Q structure is composed of a two-stage low noise amplifier (LNA), I-Q generator, mixer, transimpedance amplifier (TIA), a two-stage biquad band pass filter (BPF), and a differential-to-single (DTS) amplifier. The TIA and the BPF employ a DC offset cancellation (DCOC) circuit to suppress the strong reflection signal and TX-RX leakage. The RX chain exhibits an overall gain of 100 dB. The proposed radar transceiver is fabricated using a 65 nm CMOS technology. The transceiver consumes 220 mW from a 1 V supply voltage and has 4.84 mm2 die size including all pads. The prototype FMCW radar is realized with the proposed transceiver and Yagi antenna to verify the radar functionality, such as the distance and angle of targets.
12
KUNISHIMA, H., H. KOGA, O. MUTA e Y. AKAIWA. "Joint Use of Adaptive Equalization and Cyclic Noise Cancellation for Band-Limited OQAM Based Multi-Carrier Transmission in Power-Line Communication Systems". IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E91-A, n. 11 (1 novembre 2008): 3112–20. http://dx.doi.org/10.1093/ietfec/e91-a.11.3112.
13
Le, Anh Tuyen, Le Chung Tran, Xiaojing Huang e Yingjie Jay Guo. "Analog Least Mean Square Loop for Self-Interference Cancellation: A Practical Perspective". Sensors 20, n. 1 (3 gennaio 2020): 270. http://dx.doi.org/10.3390/s20010270.
Abstract (sommario):
Self-interference (SI) is the key issue that prevents in-band full-duplex (IBFD) communications from being practical. Analog multi-tap adaptive filter is an efficient structure to cancel SI since it can capture the nonlinear components and noise in the transmitted signal. Analog least mean square (ALMS) loop is a simple adaptive filter that can be implemented by purely analog means to sufficiently mitigate SI. Comprehensive analyses on the behaviors of the ALMS loop have been published in the literature. This paper proposes a practical structure and presents an implementation of the ALMS loop. By employing off-the-shelf components, a prototype of the ALMS loop including two taps is implemented for an IBFD system operating at the carrier frequency of 2.4 GHz. The prototype is firstly evaluated in a single carrier signaling IBFD system with 20 MHz and 50 MHz bandwidths, respectively. Measured results show that the ALMS loop can provide 39 dB and 33 dB of SI cancellation in the radio frequency domain for the two bandwidths, respectively. Furthermore, the impact of the roll-off factor of the pulse shaping filter on the SI cancellation level provided by the prototype is presented. Finally, the experiment with multicarrier signaling shows that the performance of the ALMS loop is the same as that in the single carrier system. These experimental results validate the theoretical analyses presented in our previous publications on the ALMS loop behaviors.
14
Kim, J., L. Udpa e S. Udpa. "Multi-stage adaptive noise cancellation for ultrasonic NDE". NDT & E International 34, n. 5 (luglio 2001): 319–28. http://dx.doi.org/10.1016/s0963-8695(00)00046-3.
15
Lv, Risheng, Weiping Chen e Xiaowei Liu. "A High-Dynamic-Range Switched-Capacitor Sigma-Delta ADC for Digital Micromechanical Vibration Gyroscopes". Micromachines 9, n. 8 (27 luglio 2018): 372. http://dx.doi.org/10.3390/mi9080372.
Abstract (sommario):
This paper presents a multi-stage noise shaping (MASH) switched-capacitor (SC) sigma-delta (ΣΔ) analog-to-digital converter (ADC) composed of an analog modulator with an on-chip noise cancellation logic and a reconfigurable digital decimator for MEMS digital gyroscope applications. A MASH 2-1-1 structure is employed to guarantee an absolutely stable modulation system. Based on the over-sampling and noise-shaping techniques, the core modulator architecture is a cascade of three single-loop stages containing feedback paths for systematic optimization to avoid deterioration in conversion accuracy caused by capacitor mismatch. A digital noise cancellation logic is also included to eliminate residual quantization errors in the former two stages, and those in the last stage are shaped by a fourth-order modulation. A multi-rate decimator follows the analog modulator to suit variable gyroscope bandwidth. Manufactured in a standard 0.35 μm CMOS technology, the whole chip occupies an area of 3.8 mm2. Experimental results show a maximum signal-to-noise ratio (SNR) of 100.2 dB and an overall dynamic range (DR) of 107.6 dB, with a power consumption of 3.2 mW from a 5 V supply. This corresponds to a state-of-the-art figure-of-merit (FoM) of 165.6 dB.
16
Gunnam, Leenendra Chowdary, Guo‐Ming Sung, Lei‐Wen Weng e Te‐Chia Fan. "2‐1 Switched‐current multi‐stage noise‐shaping delta–sigma modulator with a digital noise‐cancellation circuit". IET Circuits, Devices & Systems 13, n. 3 (aprile 2019): 327–36. http://dx.doi.org/10.1049/iet-cds.2018.5025.
17
Xu, Shiyun, Changjun He, Bosong Yan e Mingjiang Wang. "A Multi-Stage Acoustic Echo Cancellation Model Based on Adaptive Filters and Deep Neural Networks". Electronics 12, n. 15 (28 luglio 2023): 3258. http://dx.doi.org/10.3390/electronics12153258.
Abstract (sommario):
The presence of a large amount of echoes significantly impairs the quality and intelligibility of speech during communication. To address this issue, numerous studies and models have been conducted to cancel echo. In this study, we propose a multi-stage acoustic echo cancellation model that utilizes an adaptive filter and a deep neural network. Our model consists of two parts: the Speex algorithm for canceling linear echo, and the multi-scale time-frequency UNet (MSTFUNet) for further echo cancellation. The Speex algorithm takes the far-end reference speech and the near-end microphone signal as inputs, and outputs the signal after linear echo cancellation. MSTFUNet takes the spectra of the far-end reference speech, the near-end microphone signal, and the output of Speex as inputs, and generates the estimated near-end speech spectrum as output. To enhance the performance of the Speex algorithm, we conduct delay estimation and compensation to the far-end reference speech. For MSTFUNet, we employ multi-scale time-frequency processing to extract information from the input spectrum. Additionally, we incorporate an improved time-frequency self-attention to capture time-frequency information. Furthermore, we introduce channel time-frequency attention to alleviate information loss during downsampling and upsampling. In our experiments, we evaluate the performance of our proposed model on both our test set and the blind test set of the Acoustic Echo Cancellation challenge. Our proposed model exhibits superior performance in terms of acoustic echo cancellation and noise reverberation suppression compared to other models.
18
Wen, Jyh-Horng, e Ho-Lung Hung. "Performance analysis of multi-stage interference cancellation for ultra-wide band multiple-access communication systems". Wireless Communications and Mobile Computing 12, n. 15 (17 marzo 2011): 1371–80. http://dx.doi.org/10.1002/wcm.1068.
19
Han, Fang, Xuzhi Liu, Chao Wang, Xiao Li, Quanwen Qi, Xiaoran Li e Zicheng Liu. "A Multi-Band LNA Covering 17–38 GHz in 45 nm CMOS SOI". Electronics 11, n. 19 (10 ottobre 2022): 3255. http://dx.doi.org/10.3390/electronics11193255.
Abstract (sommario):
This paper presents a multi-band low-noise amplifier (LNA) in the 45-nm CMOS silicon-on-insulator (SOI) process. The LNA consists of three stages, with the differential cascode amplifier as the core structure. The first stage is mainly responsible for input matching to ensure favourable noise characteristics and bandwidth, while the subsequent stages increase the gain. Moreover, the LNA utilizes baluns for input/output and interstage impedance matching. Switch capacitances are added to switch the three operating bands of the LNA, which cover 17–38 GHz overall. Measurement results show that the proposed LNA achieves a gain (S21) of 23.0 dB and a noise figure (NF) of 4.0 dB.
20
Ijaz, Khalid, Muhammad Adnan, Waqas Tariq Toor, Muhammad Asim Butt, Muhammad Idrees, Usman Ali, Izaz Hassan et al. "A New Noise Shaping Approach for Sigma-Delta Modulators Using Two-Stage Feed-Forward Delays and Hybrid MASH-EFM". Electronics 12, n. 3 (1 febbraio 2023): 740. http://dx.doi.org/10.3390/electronics12030740.
Abstract (sommario):
Sigma-delta modulators use a noise-shaping technique to curtail the noise power in the band of interest during digital-to-analog conversion. Error feedback modulator employs an efficient noise transfer function for time varying inputs than any other sigma-delta modulators. However, the efficiency of the conventional noise transfer function degrades and the quantizer saturation issue provokes when the input signal reaches to full scale. This work proposes a new noise transfer function which is a combination of transfer functions of two-stage Feed-forward delays and a novel Hybrid multi-stage noise shaping-error feedback sigma-delta modulator. The noise transfer function of two-stage Feed-forward delays mitigates the concern of quantizer saturation. The noise transfer function offered by the Hybrid multi-stage noise shaping-error feedback architecture provides sustainable solutions to limit cycles and idle tones. The simulation concludes that the proposed noise-shaping approach obtains comparatively high signal-to-quantization noise ratio than the conventional error feedback modulators. Other performance parameters like spurious-free dynamic range, effective number of bits and signal-to-noise plus distortion ratio are also significantly improved.
21
BELEN, Aysu. "DESIGN OPTIMIZATION OF LOW NOISE AMPLIFIER FOR 900MHZ GSM BAND APPLICATIONS USING GREY WOLF ALGORITHM". Mühendislik Bilimleri ve Tasarım Dergisi 11, n. 3 (28 settembre 2023): 873–79. http://dx.doi.org/10.21923/jesd.1246889.
Abstract (sommario):
In this work, the design of a high-performance single-stage Low Noise Amplifier (LNA) for GSM applications is taken into consideration. LNA design is one of the key stages of a wireless communication system due to its dominance over the whole system's noise figure performance. Although it is possible to achieve a very high gain and low noise figure with the usage of multi-stage transistors, such designs would also have a high complexity and manufacturing cost. The main aim of this work is to propose a single transistor LNA design for GSM application with a gain level of 14.3 dB, return loss level of less than 15 dB, and noise figure of 1.8 dB over the operation band of 820-980 MHz. the optimal design variables of the model is obtained via Grey Wolf optimization procedure.
22
Zhang, Yu, Dan Zhang, Zhen Han e Peng Jiang. "A Joint Denoising Learning Model for Weight Update Space–Time Diversity Method". Remote Sensing 14, n. 10 (19 maggio 2022): 2430. http://dx.doi.org/10.3390/rs14102430.
Abstract (sommario):
Space–time diversity (STD) has been widely applied in underwater acoustic (UWA) communication due to its exceptional anti-multipath performance. However, underwater noise can seriously affect the processing results of STD. The conventional filtering algorithms cannot deal with the nonlinear components of underwater noise and may not work well for complex-type signals. This study proposes an improved STD method with a joint noise-reduction learning model for the above issues. We construct a noise-reduction learning model dedicated to complex-type UWA signals in the first stage. Complex-type features based on UWA data are extracted for pre-processing data, and a conditional generative adversarial network (CGAN) is used as the backbone network for noise-reduction. Residual learning is used to accomplish noise cancellation and yield noise-reduction estimates. In the second stage, an STD structure based on a weight update strategy is constructed. The STD structure can further constrain the weights of the signals from the main path, enhance the reception of the main path, and suppress the multi-access interference (MAI) caused by the spread spectrum communication. Finally, combining the signals on each path can improve the communication quality of the system based on the principle of the maximum signal-to-interference plus noise ratio (SINR). The simulation and experiments on a lake showed that the proposed method is more robust over the changing signal-to-noise ratio (SNR) and has a lower bit error rate (BER) than conventional methods.
23
TAMURA, Yu, Toru IDO e Kenji TANIGUCHI. "A Multi-Stage Second Order Dynamic Element Matching with In-Band Mismatch Noise Reduction Enhancement". IEICE Transactions on Electronics E94-C, n. 8 (2011): 1340–43. http://dx.doi.org/10.1587/transele.e94.c.1340.
24
Honcharov, K. V., e R. V. Rybalka. "Multi-Valued Automatic Cab Signalling System Based on the CDMA Technology". Science and Transport Progress, n. 6(96) (20 dicembre 2021): 14–23. http://dx.doi.org/10.15802/stp2021/258171.
Abstract (sommario):
Purpose. The work is aimed at the development of principles for the construction of multi-valued automatic cab signalling system (ACS) using the wide-band pseudorandom signals. Methodology. An analysis of existing ACS systems and modern telecommunication technologies has been performed to achieve the stated purpose. The multi-valued automatic cab signalling system CDMA-ACS has been proposed. The mentioned system utilizes wide-band pseudo-noise signals to transmit commands. System parameters: frequency band – 155...395 Hz, pseudorandom codes – 16-bit Walsh codes, spectrum spreading factor – 16, source signal bandwidth – 15 Hz, carrier modulation – DBPSK (differential binary phase-shift keying), information rate – 15 bit/sec, code combination length – 4 bits, maximum amount of commands – 256, the duration of single command transmission – 0.27 sec. Functional diagrams of generator and receiver of the multi-valued automatic cab signalling system have been designed. It has been suggested to apply the correlation method to receive the ACS signals. Findings. To investigate the proposed CDMA-ACS system the simulation modelling has been accomplished in MATLAB in two stages: at the first stage, the CDMA-ACS system was investigated as disturbance-free; at the second stage – under the influence of powerful narrow-band disturbances (traction current harmonics). It has been found that the system shows high immunity to narrow-band harmonic disturbances. The most significant harmonics of the traction current related to the system are 250 Hz and 300 Hz, since they are the closest to the carrier frequency of 275 Hz. It has been determined that errors in decoding the ACS commands occur if the signal-to-noise ratio becomes lower than -8 dB. To reduce the influence of 250 Hz and 300 Hz, harmonics the application of additional band-reject filters was proposed. Originality. For the first time, the authors of this work carried out research on the multi-valued automatic cab signalling system with the use of wide-band pseudo-random Walsh codes. Practical value. Implementation of solutions being proposed allows improving the informativeness and interference immunity for the automatic cab signalling system, reducing the duration of command transmission from the railway track to the cab.
25
Song, Ickhyun, Gyungtae Ryu, Seung Hwan Jung, John D. Cressler e Moon-Kyu Cho. "Wideband SiGe-HBT Low-Noise Amplifier with Resistive Feedback and Shunt Peaking". Sensors 23, n. 15 (28 luglio 2023): 6745. http://dx.doi.org/10.3390/s23156745.
Abstract (sommario):
In this work, the design of a wideband low-noise amplifier (LNA) using a resistive feedback network is proposed for potential multi-band sensing, communication, and radar applications. For achieving wide operational bandwidth and flat in-band characteristics simultaneously, the proposed LNA employs a variety of circuit design techniques, including a voltage–current (shunt–shunt) negative feedback configuration, inductive emitter degeneration, a main branch with an added cascode stage, and the shunt-peaking technique. The use of a feedback network and emitter degeneration provides broadened transfer characteristics for multi-octave coverage and a real impedance for input matching, respectively. In addition, the cascode stage pushes the band-limiting low-frequency pole, due to the Miller capacitance, to a higher frequency. Lastly, the shunt-peaking approach is optimized for the compensation of a gain reduction at higher frequency bands. The wideband LNA proposed in this study is fabricated using a commercial 0.13 μm silicon-germanium (SiGe) BiCMOS process, employing SiGe heterojunction bipolar transistors (HBTs) as the circuit’s core active elements in the main branch. The measurement results show an operational bandwidth of 2.0–29.2 GHz, a noise figure of 4.16 dB (below 26.5 GHz, which was the measurement limit), and a total power consumption of 23.1 mW under a supply voltage of 3.3 V. Regarding the nonlinearity associated with large-signal behavior, the proposed LNA exhibits an input 1-dB compression (IP1dB) point of −5.42 dBm at 12 GHz. These performance numbers confirm the strong viability of the proposed approach in comparison with other state-of-the-art designs.
26
Rügamer, Alexander, Cécile Mongrédien, Santiago Urquijo e Günter Rohmer. "Theoretical Analysis of Overlay GNSS Receiver Effects". International Journal of Embedded and Real-Time Communication Systems 3, n. 3 (luglio 2012): 38–53. http://dx.doi.org/10.4018/jertcs.2012070103.
Abstract (sommario):
Having given a short overview of GNSS signals and state-of-the-art multi-band front-end architectures, this paper presents a novel contribution to efficient multi-band GNSS reception. A general overlay based front-end architecture is introduced that enables the joint reception of two signals broadcast in separate frequency bands, sharing just one common baseband stage. The consequences of this overlay are analyzed for both signal and noise components. Signal overlay is shown to have a negligible impact on signal quality. It is shown that the noise floor superposition results in non-negligible degradations. However, it is also demonstrated that these degradations can be minimized by judiciously setting the relative gain between the two signal paths. As an illustration, the analytical optimal path-control expression to combine overlaid signals in an ionospheric-free pseudorange is derived for both Cramér-Rao Lower Bound and practical code tracking parameters. Finally, some practical overlay receiver and path control aspects are discussed.
27
Hoffmann, C., e P. Russer. "A low-noise high dynamic-range time-domain EMI measurement system for CISPR Band E". Advances in Radio Science 9 (1 agosto 2011): 309–15. http://dx.doi.org/10.5194/ars-9-309-2011.
Abstract (sommario):
Abstract. In this paper, a broadband time-domain EMI measurement system for measurements from 9 kHz to 18 GHz is presented that allows for compliant EMI measurements in CISPR Band E. Combining ultra-fast analog-to-digital-conversion and real-time digital signal processing on a field-programmable-gate-array (FPGA) with ultra-broadband multi-stage down-conversion, scan times can be reduced by several orders of magnitude in comparison to a traditional heterodyne EMI-receiver. The ultra-low system noise floor of 6–8 dB and the real-time spectrogram allow for the characterisation of the time-behaviour of EMI near the noise floor. EMI measurements of electronic consumer devices and electric household appliances are presented.
28
Sha, Yun Dong, Xian Zhi Cui, Feng Tong Zhao e Xiao Chi Luan. "Investigation into the Noise Characteristics Based on Rotating Instabilities Mechanism in a Multi-Stage Axial Compressor". Applied Mechanics and Materials 160 (marzo 2012): 366–72. http://dx.doi.org/10.4028/www.scientific.net/amm.160.366.
Abstract (sommario):
Rotating instability can be observed in the tip flow region of axial compressor stage while stable operation. In order to investigate the noise characteristics in a multi-stage axial compressor, the noise inner compressor casing is measured simultaneously with the vibration of the rotor blades on a high pressure compressor component rig testing. An azimuthal mode analysis and theoretical formulation of the rotating source mechanism are applied to the unsteady pressure at the casing wall immediately upstream of the inlet plane of the rotor. It is shown that RIs might be described by a group of superimposed modes. This is the reason why RIs can be identified as an amplitude increase in a frequency band. The mode orders of RI are consecutively numbered riseing with frequency. The frequency in the source frame (ωN) closed to the frequency in the rotating frame (ωN) can be got well recovered. The results presented in this paper can be a reference for further understanding of the characteristics of unsteady flow field and the effects of the high intensity sound waves on the rotor blades.
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Sampath Kumar, V., e Kartik Upreti. "Novel low noise amplifier approach for deep brain stimulation". Journal of Physics: Conference Series 2570, n. 1 (1 agosto 2023): 012033. http://dx.doi.org/10.1088/1742-6596/2570/1/012033.
Abstract (sommario):
Abstract This paper presents an analysis for a multi-stage Low Noise Amplifier (LNA) for application on deep brain stimulation. A low noise amplifier (LNA) with high gain, moderate bandwidth and reduced noise is designed and simulated using LT Spice and PTM BSIM4 CMOS models. The novel LNA circuit topology is proposed which uses a cascaded style to improve mid-band gain of an LNA. The proposed LNA achieves a gain margin which ranges between 60-67 (dB), 2X times; Phase Margin which ranges between 145 to 154 (deg), 3X times; Gain which ranges between 66 to 75 (dB), 2X times and bandwidth from kHz to MHz range. The current biasing circuit is used for enhancing stability and gain range. Also, optimal noise figure is achieved with the help of cascading input matching along with source degeneration technique.
30
Rahman, Md Habibur, Mohammad Abrar Shakil Sejan, Seung-Geun Yoo, Min-A. Kim, Young-Hwan You e Hyoung-Kyu Song. "Multi-User Joint Detection Using Bi-Directional Deep Neural Network Framework in NOMA-OFDM System". Sensors 22, n. 18 (15 settembre 2022): 6994. http://dx.doi.org/10.3390/s22186994.
Abstract (sommario):
Non-orthogonal multiple access (NOMA) has great potential to implement the fifth-generation (5G) requirements of wireless communication. For a NOMA traditional detection method, successive interference cancellation (SIC) plays a vital role at the receiver side for both uplink and downlink transmission. Due to the complex multipath channel environment and prorogation of error problems, the traditional SIC method has a limited performance. To overcome the limitation of traditional detection methods, the deep-learning method has an advantage for the highly efficient tool. In this paper, a deep neural network which has bi-directional long short-term memory (Bi-LSTM) for multiuser uplink channel estimation (CE) and signal detection of the originally transmitted signal is proposed. Unlike the traditional CE schemes, the proposed Bi-LSTM model can directly recover multiuser transmission signals suffering from channel distortion. In the offline training stage, the Bi-LTSM model is trained using simulation data based on channel statistics. Then, the trained model is used to recover the transmitted symbols in the online deployment stage. In the simulation results, the performance of the proposed model is compared with the convolutional neural network model and traditional CE schemes such as MMSE and LS. It is shown that the proposed method provides feasible improvements in performance in terms of symbol-error rate and signal-to-noise ratio, making it suitable for 5G wireless communication and beyond.
31
Kumar Vishnoi, Manoj, e Satya Sai Srikant. "Design Considerations of Reconfigurable CMOS Mixers for Multi-Standard Communication Receiver Systems". International Journal of Reconfigurable and Embedded Systems (IJRES) 7, n. 3 (1 novembre 2018): 160. http://dx.doi.org/10.11591/ijres.v7.i3.pp160-166.
Abstract (sommario):
This paper has been carried out the study of reconfigurable wide-band mixers that can do the frequency conversion and gain variation standards with low noise and high linearity used in multi-mode and multi-standard receivers. Over the last few years reconfigurability has become very popular in adopting technology to meet the wideband wireless communication specifications that is compatible with multi-standards like GPS (1.57 GHz), WLAN (2.4 GHz - 5.9 GHz), Bluetooth (2.402 – 2.483 GHz) and ZigBee (0.784 - 0.915 GHz) in low power consumption environment. The reconfigurability can be achieved between low and high band modes through power switching in RF frequency mixers. It can be achieved by flipping the input RF signal between gate and source terminal of input transistor and altering the trans-impedance stage output. With the concept of reconfigurable transistor pair with open and short circuit stubs, one can not only find the configurable gain with center frequencies 7.355, 8.65, 11.35 and 12.65 GHz but also with high power efficiency. Tow Thomas Bi-Quad Topology other than the traditional current commuting technique for the second order trans-impedance amplifier stage, works as a current mode filter over a tunable bandwidth. The active Gilbert mixers are used widely in most of communication system, due to its significance gain, perfect isolation, and linearity in response.
32
Kumar Vishnoi, Manoj, e Satya Sai Srikant. "Design Considerations of Reconfigurable CMOS Mixers for Multi-Standard Communication Receiver Systems". International Journal of Reconfigurable and Embedded Systems (IJRES) 7, n. 3 (1 novembre 2018): 166. http://dx.doi.org/10.11591/ijres.v7.i3.pp166-172.
Abstract (sommario):
This paper has been carried out the study of reconfigurable wide-band mixers that can do the frequency conversion and gain variation standards with low noise and high linearity used in multi-mode and multi-standard receivers. Over the last few years reconfigurability has become very popular in adopting technology to meet the wideband wireless communication specifications that is compatible with multi-standards like GPS (1.57 GHz), WLAN (2.4 GHz - 5.9 GHz), Bluetooth (2.402 – 2.483 GHz) and ZigBee (0.784 - 0.915 GHz) in low power consumption environment. The reconfigurability can be achieved between low and high band modes through power switching in RF frequency mixers. It can be achieved by flipping the input RF signal between gate and source terminal of input transistor and altering the trans-impedance stage output. With the concept of reconfigurable transistor pair with open and short circuit stubs, one can not only find the configurable gain with center frequencies 7.355, 8.65, 11.35 and 12.65 GHz but also with high power efficiency. Tow Thomas Bi-Quad Topology other than the traditional current commuting technique for the second order trans-impedance amplifier stage, works as a current mode filter over a tunable bandwidth. The active Gilbert mixers are used widely in most of communication system, due to its significance gain, perfect isolation, and linearity in response.
33
Zhu, Y., Y. Chen, J. H. Yu, C. Domier, G. Yu, X. Liu, G. Kramer et al. "System-on-chip approach microwave imaging reflectometer on DIII-D tokamak". Review of Scientific Instruments 93, n. 11 (1 novembre 2022): 113509. http://dx.doi.org/10.1063/5.0099170.
Abstract (sommario):
System-on-chip millimeter wave integrated circuit technology is used on the two-dimensional millimeter-wave imaging reflectometer (MIR) upgrade for density fluctuation imaging on the DIII-D tokamak fusion plasma. Customized CMOS chips have been successfully developed for the transmitter module and receiver module array, covering the 55–75 GHz working band. The transmitter module has the capability of simultaneously launching eight tunable probe frequencies (>0 dBm output power each). The receiver enclosure contains 12 receiver modules in two vertical lines. The quasi-optical local oscillator coupling of previous MIR systems has been replaced with an internal active frequency multiplier chain for improved local oscillator power delivery and flexible installation in a narrow space together with improved shielding against electromagnetic interference. The 55–75 GHz low noise amplifier, used between the receiver antenna and the first-stage mixer, significantly improves module sensitivity and suppresses electronics noise. The receiver module has a 20 dB gain improvement compared with the mini-lens approach and better than −75 dBm sensitivity, and its electronics noise temperature has been reduced from 55 000 K down to 11 200 K. The V-band MIR system is developed for co-located multi-field investigation of MHD-scale fluctuations in the pedestal region with W-band electron cyclotron emission imaging on DIII-D tokamak.
34
Mirza, Jawad, Salman Ghafoor, Ammar Armghan, Osama I. Elhamrawy, Laiq Jamal, Musab Magam, Sharif Iqbal Mitu Sheikh e Khurram Karim Qureshi. "Performance Enhancement of Ytterbium-Doped Fiber Amplifier Employing a Dual-Stage In-Band Asymmetrical Pumping". Micromachines 13, n. 9 (7 settembre 2022): 1488. http://dx.doi.org/10.3390/mi13091488.
Abstract (sommario):
The performance of doped fiber amplifiers can be enhanced significantly with the help of multi-stage pumping technique provided that various critical parameters of pumps including their optical power and wavelength are optimized. We report the performance enhancement of a ytterbium doped fiber amplifier (YDFA) for a 1.02–1.08 μm spectral region with an optimized design based on a novel dual-stage in-band asymmetrical pumping scheme. By accurately adjusting the optical power and wavelength of pumps in both the stages, a record peak gain of around 62.5 dB and output power of 4.5 W are achieved for a signal wavelength of 1.0329 μm at an optimized length of Ytterbium-doped silica fiber and optimized doping concentration of Yb3+. Moreover, a minimum noise figure (NF) of 4 dB is observed for a signal wavelength of 1.0329 μm at the optimized parameters. Similarly, the effect of using high and low pump powers at the first and the second stage, respectively, on NF of the amplifier is also investigated at different values of signal powers. It is observed that the value of NF increases significantly by using high pump power at the first stage and low pump power at the second stage.
35
A. S.,, Anand Swamy, Mamatha A. S.,, Shylashree N. e V. Sridhar. "Lossless Compression of Hyperspectral Imagery by Assimilating Decorrelation and Pre-processing with Efficient Displaying using Multi Scale HDR Approach". WSEAS TRANSACTIONS ON SIGNAL PROCESSING 18 (18 maggio 2022): 77–88. http://dx.doi.org/10.37394/232014.2022.18.11.
Abstract (sommario):
The instinctive essence of the Hyperspectral imagery cube is its immense information having both spatial and spectral correlation. In the interest of reducing the storage and bandwidth requisites, an effective lossless Hyperspectral compression system has been proposed. The imagery is enforced to preprocessing stage prior to decorrelation. Preprocessing stage comprises band normalization and band ordering techniques. A new technique named Greedy heap sorting is addressed to sort the bands. The proposed strategy accords with a Compression ratio (CR) of 8.12 and bits per pixel (bpp) of 1.67. The performance of the system is comparable with the existing contemporary algorithms for lossless Hyperspectral image compression in terms of CR and bpp. Experiment conducted on AVIRIS scenes substantiates that the proposed methodology surpasses the IP3-OBPS-BPS method by percentage increase of 116.44 in CR and percentage decrease of 58.49 in bpp. Multiscale High Dynamic Range (HDR) approach is used to display Hyperspectral image on Low Dynamic Range (LDR) devices. The Edge Preserving Filters (EPF) are used for the decomposition of the image into base layers and detail layer. The details are perceived better in the display of Hyperspectral images. Among the Edge Preserving Filters, Weighted Least Square filter gave better perceiving with the Peak Signal to Noise Ratio of 53.5108 dB, which is better than other existing methods.
36
Han, Jingyu, Yu Jiang, Guiliang Guo e Xu Cheng. "A Reconfigurable Analog Baseband Circuitry for LFMCW RADAR Receivers in 130-nm SiGe BiCMOS Process". Electronics 9, n. 5 (18 maggio 2020): 831. http://dx.doi.org/10.3390/electronics9050831.
Abstract (sommario):
A highly reconfigurable open-loop analog baseband circuitry with programmable gain, bandwidth and filter order are proposed for integrated linear frequency modulated continuous wave (LFMCW) radar receivers in this paper. This analog baseband chain allocates noise, gain and channel selection specifications to different stages, for the sake of noise and linearity tradeoffs, by introducing a multi-stage open-loop cascaded amplifier/filter topology. The topology includes a course gain tuning pre-amplifier, a folded Gilbert variable gain amplifier (VGA) with a symmetrical dB-linear voltage generator and a 10-bit R-2R DAC for fine gain tuning, a level shifter, a programmable Gm-C low pass filter, a DC offset cancellation circuit, two fixed gain amplifiers with bandwidth extension and a novel buffer amplifier with active peaking for testing purposes. The noise figure is reduced with the help of a low noise pre-amplifier stage, while the linearity is enhanced with a power-efficient buffer and a novel high linearity Gm-C filter. Specifically, the Gm-C filter improves its linearity specification with no increase in power consumption, thanks to an alteration of the trans-conductor/capacitor connection style, instead of pursuing high linearity but power-hungry class-AB trans-conductors. In addition, the logarithmic bandwidth tuning technique is adopted for capacitor array size minimization. The linear-in-dB and DAC gain control topology facilitates the analog baseband gain tuning accuracy and stability, which also provides an efficient access to digital baseband automatic gain control. The analog baseband chip is fabricated using 130-nm SiGe BiCMOS technology. With a power consumption of 5.9~8.8 mW, the implemented circuit achieves a tunable gain range of −30~27 dB (DAC linear gain step guaranteed), a programmable −3 dB bandwidth of 18/19/20/21/22/23/24/25 MHz, a filter order of 3/6 and a gain resolution of better than 0.07 dB.
37
Lee, Hyunkyu, e Sanggeun Jeon. "A Q-Band CMOS Image-Rejection Receiver Integrated with LO and Frequency Dividers". Electronics 12, n. 14 (13 luglio 2023): 3069. http://dx.doi.org/10.3390/electronics12143069.
Abstract (sommario):
This paper presents a Q-band image-rejection receiver using a 65 nm CMOS technology. For a high image-rejection ratio (IMRR), the Q-band receiver employs the Hartley architecture which consists of a Q-band low-noise amplifier, two down-conversion mixers, a 90° hybrid coupler, and two IF baluns. In addition, a Q-band fundamental voltage-controlled oscillator (VCO) and a frequency divider chain divided by 256 are integrated into the receiver for LO. A charge injection technique is employed in the mixers to reduce the DC power while maintaining a high conversion gain and linearity. The VCO adopts a cross-coupled topology to secure stable oscillation with high output power in the Q-band. The frequency divider chain is composed of an injection-locked frequency divider (ILFD) and a multi-stage current-mode logic (CML) divider to achieve a high division ratio of 256, which facilitates the LO signal locking to an external phase-locked loop. An inductive peaking is employed in the ILFD to widen the locking range. The Q-band image-rejection receiver exhibits a peak conversion gain of 16.4 dB at 43 GHz. The IMRR is no less than 35.6 dBc at the IF frequencies from 1.5 to 5 GHz.
38
Chen, Yaogang, Qian Sun e Jun Hu. "Quantitatively Estimating of InSAR Decorrelation Based on Landsat-Derived NDVI". Remote Sensing 13, n. 13 (22 giugno 2021): 2440. http://dx.doi.org/10.3390/rs13132440.
Abstract (sommario):
As a by-product of Interferometric Synthetic Aperture Radar (SAR, InSAR) technique, interferometric coherence is a measure of the decorrelation noise for InSAR observation, where the lower the coherence value, the more serious the decorrelation noise. In the densely vegetated area, the coherence value could be too low to obtain any valuable signals, leading to the degradation of InSAR performance and the possible waste of expensive SAR data. Normalized Difference Vegetation Index (NDVI) value is a measure of the vegetation coverage and can be estimated from the freely available optical satellite images. In this paper, a multi-stage model is established to quantitatively estimate the decorrelation noise for vegetable areas based on Landsat-derived NDVI prior to the acquisition of SAR data. The modeling process is being investigated with the L-band ALOS-1/PALSAR-1 data and the Landsat-5 optical data acquired in the Meitanba area of Hunan Province, China. Furthermore, the reliability of the established model is verified in the Longhui area, which is situated near the Meitanba area. The results demonstrate that the established model can quantitatively estimate InSAR decorrelation associated with the vegetation coverage.
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Menakadevi, T., J. Arivudainambi e M. Sulochana. "Multi-Resolution Transforms Based Robust Image Enhancement for High Frequency Colour Images". Advanced Materials Research 933 (maggio 2014): 762–67. http://dx.doi.org/10.4028/www.scientific.net/amr.933.762.
Abstract (sommario):
An Image Resolution Enhancement Technique based on Interpolation of the high frequency sub-band of colour images obtained by Discrete Wavelet Transform and the input colour image is proposed in this paper. Interpolation determines the intermediate values on the basis of observed values. One of the commonly used interpolation technique is Bicubic Interpolation. The edges are enhanced by introducing an intermediate stage by using Stationary Wavelet Transform. It is designed to overcome the lack of Translation-Invariance of Discrete Wavelet Transform. This is widely used in Signal Denoising and Pattern Recognition. Discrete Wavelet Transform is applied in order to decompose an input colour image into different sub-bands. Then the high frequency sub-bands as well as the input colour image are interpolated separately. The interpolated high frequency sub-bands and the Stationary Wavelet Transform high frequency sub-bands have the same size which means they can be added with each other. The new corrected high frequency sub-bands can be interpolated further for higher enlargement. Then all these sub-bands are combined with interpolated input image for new high resolution image by using Inverse Discrete Wavelet Transform. This has been done by MATLAB. The Peak Signal-Noise Ratio was obtained upto 5dB greater than the conventional and state-of-art image resolution enhancement techniques.
40
Phuong, Linh Ta, Bernard Journet e Duong Bach Gia. "A microwave active filter for nanosatellite’s receiver front-ends at s-bands". International Journal of Electrical and Computer Engineering (IJECE) 9, n. 2 (1 aprile 2019): 973. http://dx.doi.org/10.11591/ijece.v9i2.pp973-981.
Abstract (sommario):
<p>In satellite technology, the communication between space segment and ground segment plays a vital role in the success of the mission. This paper is targeted at study, design and fabrication of a microwave active filter for the receiver front-ends using coupled line filter structure, which can be applied to the nanosatellite’s communication subsystem. The whole active filter module is a combination of a microstrip bandpass filter and a preceding two-stage wideband low noise amplifier using FET devices. The proposed module operates in the frequency range of 2 - 2.4 GHz, which can be divided to 10 frequency slots of about 40 MHz for each. These frequency slots will be used for the S-band multi-frequency receiving function of the ground station, as well as the nanosatellite. The simulated and measured results of this active filter configuration are presented.</p>
41
Sarker, Md, e Ickhyun Song. "Design and Analysis of fT-Doubler-Based RF Amplifiers in SiGe HBT Technology". Electronics 9, n. 5 (8 maggio 2020): 772. http://dx.doi.org/10.3390/electronics9050772.
Abstract (sommario):
For performance-driven systems such as space-based applications, it is important to maximize the gain of radio-frequency amplifiers (RFAs) with a certain tolerance against radiation, temperature effects, and small form factor. In this work, we present a K-band, compact high-gain RFA using an fT-doubler topology in a silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) technology platform. The through-silicon vias (TSVs), typically used for small-size chip packaging purposes, have been effectively utilized as an adjustable matching element for input impedance, reducing the overall area of the chip. The proposed RFA, fabricated in a modest 0.35 µm SiGe technology, achieves a gain of 14.1 dB at 20 GHz center frequency, and a noise figure (NF) of 11.2 dB at the same frequency, with a power consumption of 3.3 mW. The proposed design methodology can be used for achieving high gain, avoiding a complex multi-stage amplifier design approach.
42
Sun, Qiyang, Xia Wang, Changda Yan e Xin Zhang. "VQ-InfraTrans: A Unified Framework for RGB-IR Translation with Hybrid Transformer". Remote Sensing 15, n. 24 (7 dicembre 2023): 5661. http://dx.doi.org/10.3390/rs15245661.
Abstract (sommario):
Infrared (IR) images containing rich spectral information are essential in many fields. Most RGB-IR transfer work currently relies on conditional generative models to learn and train IR images for specific devices and scenes. However, these models only establish an empirical mapping relationship between RGB and IR images in a single dataset, which cannot achieve the multi-scene and multi-band (0.7–3 μm and 8–15 μm) transfer task. To address this challenge, we propose VQ-InfraTrans, a comprehensive framework for transferring images from the visible spectrum to the infrared spectrum. Our framework incorporates a multi-mode approach to RGB-IR image transferring, encompassing both unconditional and conditional transfers, achieving diverse and flexible image transformations. Instead of training individual models for each specific condition or dataset, we propose a two-stage transfer framework that integrates diverse requirements into a unified model that utilizes a composite encoder–decoder based on VQ-GAN, and a multi-path transformer to translate multi-modal images from RGB to infrared. To address the issue of significant errors in transferring specific targets due to their radiance, we have developed a hybrid editing module to precisely map spectral transfer information for specific local targets. The qualitative and quantitative comparisons conducted in this work reveal substantial enhancements compared to prior algorithms, as the objective evaluation metric SSIM (structural similarity index) was improved by 2.24% and the PSNR (peak signal-to-noise ratio) was improved by 2.71%.
43
Rau, J. Y., J. P. Jhan e C. Y. Huang. "ORTHO-RECTIFICATION OF NARROW BAND MULTI-SPECTRAL IMAGERY ASSISTED BY DSLR RGB IMAGERY ACQUIRED BY A FIXED-WING UAS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1/W4 (26 agosto 2015): 67–74. http://dx.doi.org/10.5194/isprsarchives-xl-1-w4-67-2015.
Abstract (sommario):
Miniature Multiple Camera Array (MiniMCA-12) is a frame-based multilens/multispectral sensor composed of 12 lenses with narrow band filters. Due to its small size and light weight, it is suitable to mount on an Unmanned Aerial System (UAS) for acquiring high spectral, spatial and temporal resolution imagery used in various remote sensing applications. However, due to its wavelength range is only 10 nm that results in low image resolution and signal-to-noise ratio which are not suitable for image matching and digital surface model (DSM) generation. In the meantime, the spectral correlation among all 12 bands of MiniMCA images are low, it is difficult to perform tie-point matching and aerial triangulation at the same time. In this study, we thus propose the use of a DSLR camera to assist automatic aerial triangulation of MiniMCA-12 imagery and to produce higher spatial resolution DSM for MiniMCA12 ortho-image generation. Depending on the maximum payload weight of the used UAS, these two kinds of sensors could be collected at the same time or individually. In this study, we adopt a fixed-wing UAS to carry a Canon EOS 5D Mark2 DSLR camera and a MiniMCA-12 multi-spectral camera. For the purpose to perform automatic aerial triangulation between a DSLR camera and the MiniMCA-12, we choose one master band from MiniMCA-12 whose spectral range has overlap with the DSLR camera. However, all lenses of MiniMCA-12 have different perspective centers and viewing angles, the original 12 channels have significant band misregistration effect. Thus, the first issue encountered is to reduce the band misregistration effect. Due to all 12 MiniMCA lenses being frame-based, their spatial offsets are smaller than 15 cm and all images are almost 98% overlapped, we thus propose a <b>modified projective transformation</b> (MPT) method together with two systematic error correction procedures to register all 12 bands of imagery on the same image space. It means that those 12 bands of images acquired at the same exposure time will have same interior orientation parameters (IOPs) and exterior orientation parameters (EOPs) after band-to-band registration (BBR). Thus, in the aerial triangulation stage, the master band of MiniMCA-12 was treated as a reference channel to link with DSLR RGB images. It means, all reference images from the master band of MiniMCA-12 and all RGB images were triangulated at the same time with same coordinate system of ground control points (GCP). Due to the spatial resolution of RGB images is higher than the MiniMCA-12, the GCP can be marked on the RGB images only even they cannot be recognized on the MiniMCA images. Furthermore, a one meter gridded digital surface model (DSM) is created by the RGB images and applied to the MiniMCA imagery for ortho-rectification. Quantitative error analyses show that the proposed BBR scheme can achieve 0.33 pixels of average misregistration residuals length and the co-registration errors among 12 MiniMCA ortho-images and between MiniMCA and Canon RGB ortho-images are all less than 0.6 pixels. The experimental results demonstrate that the proposed method is robust, reliable and accurate for future remote sensing applications.
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Zhang, Jili, Yu Li, Shengxi Diao, Xuefei Bai e Fujiang Lin. "A 3 mW 1.2–3.6 GHz Multi-Phase PLL-Based Clock Generator with TDC Assisted Auto-Calibration of Loop Bandwidth". Journal of Circuits, Systems and Computers 27, n. 08 (12 aprile 2018): 1850117. http://dx.doi.org/10.1142/s0218126618501177.
Abstract (sommario):
A PLL-based clock generator with an auto-calibration circuit is presented. The auto-calibration circuit employs an oscillator-based time-to-digital converter (TDC) to achieve a constant loop bandwidth and fast lock time. The TDC measures the operating frequency of [Formula: see text]-stage ring-VCO with a resolution of [Formula: see text] in a time period of [Formula: see text]. The measured frequency is utilized to calibrate loop bandwidth and VCO frequency. The clock generator is designed in 40[Formula: see text]nm CMOS process and operates from 1.2[Formula: see text]GHz to 3.6[Formula: see text]GHz with 8-phase outputs. The total lock time is less than 3[Formula: see text][Formula: see text]s including calibration and PLL closed-loop locking processes. Operating at 3.2[Formula: see text]GHz, the in-band phase noise is better than [Formula: see text][Formula: see text]dBc/Hz and root-mean square (RMS) jitter integrated from 10[Formula: see text]KHz to 100[Formula: see text]MHz is 2 ps. In the entire operating range, the RMS jitter and reference spur are better than 5.5[Formula: see text]ps and [Formula: see text][Formula: see text]dBc/Hz, respectively. The clock generator consumes only 3[Formula: see text]mW from 1.1[Formula: see text]V supply at high-frequency end and 1.6[Formula: see text]mW at low-frequency end. The active area is only 0.04[Formula: see text]mm2 including on-chip loop filter and auto-calibration circuits.
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Eissa, Mohamed, e Gunter Fischer. "(Digital Presentation) Sub-THz Front Ends for Future Communication and Sensing Technologies in 130nm Sige Bicmos Technology". ECS Meeting Abstracts MA2022-02, n. 32 (9 ottobre 2022): 1203. http://dx.doi.org/10.1149/ma2022-02321203mtgabs.
Abstract (sommario):
Introduction: Beyond the-5G technologies are targeting the available bandwidth (BW) in the D-band and J-band. This promises for very high speed communication and sensing accuracy. Although the advantages of operating beyond 100 GHz from the application point of view, it requires a lot of research and development to design a reliable and power efficient chipsets. In this presentation we will go through the design of wideband 240 GHz transmitter (Tx) and receiver (Rx). Firstly an overview about the link budget analysis will be given, then the design of the local carrier signal generator will be discussed. The wideband Txs and Rxs are to be presented with frequency channelizing concept. At the end the results of the wireless links will be demonstrated. Link Budget Analysis: Operating at sub-THz frequencies approaching the transistor fT put a lot of constraints on the system link budget. The elevated noise figure together with the limited maximum Pout of the transistors lead to solutions which might be limited in BW or power efficiency. Hence the design architecture need to be optimized taking into account the elevated power consumption and heat dissipation. Carrier Generation: Several approaches could be followed to generate the sub-THz carrier frequency. For a power efficient solution the fundamental oscillators promise for a power efficient solution but with limited phase noise performance and tuning range. Such a solution is more common for imaging systems operating at a single frequency. In order to achieve wider tuning ranges for multi-channel scenario or FMCW radar systems, the frequency multiplication chains are common, whereas the multiplication factor depends on the system parameters. Sub-THz Rx: Different approaches were followed to realize a wideband sub-THz Rx. For some technologies the transistors ft does not promise the realization of low noise amplifiers (LNA) with reasonable noise figure, gain and BW. Hence the mixer first approach were followed trying to optimize the noise figure of the down conversion mixer as much as possible. This also enhances the input compression point (IP1dB) of the Rx which is better for monostatic radar applications. On the other hand, if the technology in use allows the development of well performing LNA’s, the LNA first approach was followed to enhance the all over NF of the receiver and ease the implementation of IQ Rxs. In our work an LNA was implemented followed by IQ downconversion mixers and baseband chain as presented in [3]. Sub-THz Tx: The Tx main challenging performance parameter in the sub-THz frequency range is to achieve high output compression point across the required BW with as high efficiency as possible. Increasing the power handling capabilities of the power amplifiers (PA) by increasing the transistors sizes of the output stages, leads to low output impedance and hence higher impedance transformation ratios for the matching structures and eventually narrow band designs. Hence the power combining architectures were proposed as an alternative to increase the output power either by combining on-chip or combining in air. In this work a fully integrated IQ Tx is to be presented with on-chip LO chain and 4-way power combined power amplifier. Baseband Signal Generation and Processing The baseband topology depend on the application. For mobile communication or localization use cases a wideband channels are not available directly from the digital processors, a kind of channel bonding is required either in the digital domain or in the analog domain. As a proof of concept we present here 3-IQ frequency interleaving combiner. Wireless Link Demonstrator Two demonstrators are to be presented. The first demonstrator is transmitting a broadband IQ signal generated from an arbitrary wave generator wirelessly utilizing an IQ 240GHz Tx and Rx. Data rates up to 100 Gbps were demonstrated across a 1m of wireless link. The second demonstrator includes the implementation of 3-channel IQ channelizer to create the complex modulated signal at several intermediate frequencies (IFs) and then upconverted to the 240GHz carrier signal. On the Rx side the de-channelizer convert the down modulated signal to three IQ channels. Data rates up to 8Gbps were demonstrated wirelessly with the channelization with potential of further enhancements for more channels integration. Outlook The future of the sub-THz wireless links for high speed communication and localizations goes towards implementing phased array and MIMO systems. This requires the research community to develop novel architectures to develop large scale arrays with acceptable power consumptions and suitable packaging solution. On the baseband side also the channel bonding solutions are still in an early stage, requiring more work to bond modularly larger number of channels.
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Буров, Р. И., А. И. Гревцев, В. И. Зимарин e В. В. Капитанов. "TECHNIQUE OF THE SUBSTANTIATION OF DEMANDS TO THE ANALOG PART OF THE DIGITAL RADIORECEIVER RECEPTION SECTION". ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА 19, n. 4 (7 settembre 2023): 103–10. http://dx.doi.org/10.36622/vstu.2023.19.4.013.
Abstract (sommario):
при проектировании аналоговой части приемного тракта цифрового радиоприемника, построенного по супергетеродинной схеме, применительно к узкополосным сигналам, возникает необходимость использовать методический аппарат, позволяющий учитывать влияние чувствительности, коэффициента шума, коэффициента усиления аналогового тракта, дискретизации при аналого-цифровом преобразовании, наложение спектров в процессе дискретизации и выбор номиналов промежуточных частот. Разработка методики обоснования требований к аналоговой части приемного тракта цифрового радиоприемника. Элементами новизны представленного подхода является учет многообразия факторов, влияющих на структуру элементов аналогового тракта, на основе предъявляемых требований к характеристикам разрабатываемых цифровых радиоприемников. Показано, каким образом на этапе проектирования осуществляется предварительный выбор структуры тракта принимаемой частоты, усилительных приборов, исходя из условий многосигнальной избирательности, выбор минимального значения первой промежуточной частоты с учетом обеспечения подавления помехи по побочным каналам первого преобразования частоты, значений частоты дискретизации и номинала второй промежуточной частоты, а также приводятся структурные схемы трактов. Предложенный подход позволяет обосновать требования к построению аналоговой части приемного тракта цифрового радиоприемника, а также к параметрам его элементов when designing of an analogue part of a digital radioreceiver reception section based on superheterodyne principle, with reference to narrow-band signals, there is a necessity to use the methodical apparatus, allowing to consider agency of sensitivity, a noise factor, coefficient of amplification of an analogue section, a digitization at an analogue-digital conversion, superposition of spectra in the course of a digitization and sampling of face values of intermediate frequencies. The paper is devoted to the development of a technique for substantiating the requirements for the analog part of the receiving path of a digital radio receiver. The novelty of the presented approach is the consideration of the variety of factors that affect the structure of the elements of the analog path, based on the requirements for the characteristics of the developed digital radio receivers. It is shown how, at the design stage, the preliminary selection of the structure of the received frequency path, amplifying devices, based on the conditions of multi-signal selectivity, the choice of the minimum value of the first intermediate frequency, taking into account the suppression of interference in the side channels of the first frequency conversion, frequency values sampling and nominal value of the second intermediate frequency, as well as block diagrams of the paths. The proposed approach allows justifying the requirements for the construction of the analog part of the receiving path of a digital radio receiver, as well as for the parameters of its elements
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Subash, Jenita, e Kalaivani S. "Noise Cancellation in Computed Tomography Images through Adaptive Multi-Stage Noise Removal Paradigm". International Journal of Advanced Computer Science and Applications 12, n. 12 (2021). http://dx.doi.org/10.14569/ijacsa.2021.0121221.
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Roy, Apratim, e A. Harun Rashid. "Optimization of building blocks for multi-stage 17–44 dB 6.1–9.6 mW 90-nm K-band front-ends". Open Engineering 3, n. 4 (1 gennaio 2013). http://dx.doi.org/10.2478/s13531-013-0120-y.
Abstract (sommario):
AbstractIn this article, five two-stage ∼6-mW and four three-stage ∼9-mW matched amplifier architectures are proposed to establish optimization procedure and quantify relative merits of cascode (CC), common-gate (CG), and commonsource (CS) building blocks for low-voltage low-power multi-stage front-ends. The circuits are simulated with a 90-nm CMOS technology including modeling of layout parasites. Integrated bias trees and passive port matching networks are incorporated in the K-band designs. In the face of process mismatch, variability in noise and gain figures remains <0.39 dB and <7.1 dB from the design values. The five combinations of building blocks in twostage low-power (6.1–6.6 mW) amplifiers achieve linearity (IIP3) in the range of −5.2∼–13.5 dBm, good reverse isolation (better than −26 dB), 2.89–3.82 dB noise penalties, and 17.2–25.5 dB peak forward gain. In case of threestage front-ends built with CS, CC, and CG blocks (power rating 9.2–9.6 mW), forward gain and optimized noise figures are found as >33 dB and <3.26 dB, respectively. They achieve −2.5∼18.3 dBm IIP3, <−39 dB reverse isolation, and <−17 dB minimum IRL. The results are compared with reported simulated findings on CMOS multistage amplifiers to highlight their relative advantages in terms of power requirement and decibel(gain)-per-watt.
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Sharafkhani, Naser. "An ultra-thin multi-layered metamaterial for power transformer noise absorption". Building Acoustics, 28 agosto 2021, 1351010X2110417. http://dx.doi.org/10.1177/1351010x211041704.
Abstract (sommario):
A compact multi-layered structure is proposed based on the coiled-up space concept for power transformer noise absorption at 100 and 200 Hz. Current methods of constructing multi-band absorbers are impractical for power transformer noise control due to the high coupling effect deteriorating their performance. To overcome this shortcoming, the proposed structure is composed of multiple connected layers creating two separate coiled ducts with adjustable dimensions to minimise the coupling effect. In the modelling stage, the geometrical features are optimised using the genetic algorithm to maximise the absorption coefficient and minimise the thickness. The proposed dual-tone absorber has a thickness of 43.5 mm which is significantly thinner than the existing conventional absorbers. The measurement results on a 3D-printed structure demonstrate the feasibility of the design.
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Гепко, Ігор. "M-ARY CDMA SCHEME WITH CCSK MODULATION AND PARALLEL INTERFERENCE CANCELLATION TECHNIQUE". Інфокомунікаційні та комп’ютерні технології 2, n. 02 (15 gennaio 2022). http://dx.doi.org/10.36994/2788-5518-2021-02-02-04.
Abstract (sommario):
In this paper, we tackle the problem of implementation a parallel interference cancellation scheme for multi-user detection (MUD) in M-ary CCSK-modulated CDMA system. Complexity remains the main obstacle to the practical implementation of MUD and a factor limiting, if not the very possibility, then the feasibility of using high order M-ary modulation formats for applications such as low-probability-of-intercept systems with a large spreading factor or, myriads of small self-powered IoT devices. The design of MUD algorithms for M-ary systems leads to a new round of growth in the receiver complexity comparing with the binary modulation. Demodulator has a major impact on the complexity of CDMA system. Cyclic code-shift keying (CCSK) is a modulation technique which is designed to reduce the complexity of M-ary signaling. In this, each symbol is a circularly shifted version of a single code sequence. Assuming synchronization, the receiver cyclically correlates the input signal plus noise with the base sequence and estimates the position of the correlation peak. The preliminary stage of the proposed scheme is a conventional multi-channel CDMA receiver. The preliminary estimates of the data is multiplied by user codes and amplitude estimates in the spreader, and then fed to the adder to generate the MAI estimates. After the latter are subtracted from the group signal, K-dimensional vector of cleared user signals is passed to the matched filter bank to form the refined estimates of the data. At each subsequent stage, the estimates of the output data of the previous stage are used as input data. The complexity gain is the ratio of the number of computations for finding cyclic convolution and, the amount of computations for finding M linear convolutions, i.e., M/log2M. Since the performance of the algorithm is sensitive to the reliability of the preliminary decisions, there are strict criteria for the selection of spreading codes: the length which must be an integer power of 2, the large family size, good periodic autocorrelation and good cross-correlation properties. To examine the proposed algorithm using computer simulation, we selected minimax periodic and odd-periodic complementary codes, the properties of which are close to the properties of the codes used in the CCSK scheme implemented in Link-16 protocol tactical data networks JTIDS and MIDS. Our study shows that the gain over the conventional receiver increases as the SNR increases, achieving 15 dB for BER 10-5. The system with complementary codes outperform system based on minimax PN-codes, achieving a target bit error rate at a lower SNR.