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Journal articles on the topic 'Doppler continuous wave antennae'

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Author: Grafiati

Published: 4 June 2021

Last updated: 20 February 2023

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1

Richter, Yair, Jacob Gerasimov, Nezah Balal, and Yosef Pinhasi. "Tracking of Evasive Objects Using Bistatic Doppler Radar Operating in the Millimeter Wave Regime." Remote Sensing 14, no. 4 (February 11, 2022): 867. http://dx.doi.org/10.3390/rs14040867.

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In this study, we propose a range detection (RD) ability by a continuous wave (CW) bistatic Doppler radar (RDCWB) of small and fast targets with very high range resolution. The target’s range and velocity are detected simultaneously. The scheme is based on the transmission of a continuous wave (CW) at millimeter wavelength (MMW) and the measurement of the respective Doppler shifts associated with target movements in different directions. The range resolution in this method is determined by the Doppler resolution only, without the necessity to transmit the modulated waveforms as in frequency modulation continuous wave (FMCW) or pulse radars. As the Doppler resolution in CW depends only on the time window required for processing, a very highrange resolution can be obtained. Most other systems that perform target localization use the transmission of wide-band waveforms while measuring the delay of the received signal scattered from the target. In the proposed scheme, the range resolution depends on the processed integration time of the detected signal and the velocity of the target. The transmission is performed from separated antennas and received by a single antenna. The received signal is heterodyned with a sample of the transmitted signal in order to obtain the Doppler shifts associated with the target’s movement. As in a multi-in multi-out (MIMO) configuration, the presented scheme allows for the accumulation of additional information for target classification. Data on the target’s velocity, distance, direction, and instantaneous velocity can be extracted. Using digital processing, with the additional information obtained by analyzing the difference between the resulting intermediate frequencies caused by the Doppler effect, it is possible to calculate the distance between the radar and the target at high resolution in real-time. The presented method, which was tested experimentally, proved to be highly effective, as only one receiver is required for the detection, while the transmission is carried out using a fixed, single-frequency transmission.

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2

Vierinen, Juha, Jorge L. Chau, Nico Pfeffer, Matthias Clahsen, and Gunter Stober. "Coded continuous wave meteor radar." Atmospheric Measurement Techniques 9, no. 2 (March 3, 2016): 829–39. http://dx.doi.org/10.5194/amt-9-829-2016.

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Abstract. The concept of a coded continuous wave specular meteor radar (SMR) is described. The radar uses a continuously transmitted pseudorandom phase-modulated waveform, which has several advantages compared to conventional pulsed SMRs. The coding avoids range and Doppler aliasing, which are in some cases problematic with pulsed radars. Continuous transmissions maximize pulse compression gain, allowing operation at lower peak power than a pulsed system. With continuous coding, the temporal and spectral resolution are not dependent on the transmit waveform and they can be fairly flexibly changed after performing a measurement. The low signal-to-noise ratio before pulse compression, combined with independent pseudorandom transmit waveforms, allows multiple geographically separated transmitters to be used in the same frequency band simultaneously without significantly interfering with each other. Because the same frequency band can be used by multiple transmitters, the same interferometric receiver antennas can be used to receive multiple transmitters at the same time. The principles of the signal processing are discussed, in addition to discussion of several practical ways to increase computation speed, and how to optimally detect meteor echoes. Measurements from a campaign performed with a coded continuous wave SMR are shown and compared with two standard pulsed SMR measurements. The type of meteor radar described in this paper would be suited for use in a large-scale multi-static network of meteor radar transmitters and receivers. Such a system would be useful for increasing the number of meteor detections to obtain improved meteor radar data products.

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3

Ishmael, Khaldoon, Yao Zheng, and Olga Borić-Lubecke. "Phase Correlation Single Channel Continuous Wave Doppler Radar Recognition of Multiple Sources." Sensors 22, no. 3 (January 26, 2022): 970. http://dx.doi.org/10.3390/s22030970.

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Continuous-wave Doppler radar (CWDR) can be used to remotely detect physiological parameters, such as respiration and heart signals. However, detecting and separating multiple targets remains a challenging task for CWDR. While complex transceiver architectures and advanced signal processing algorithms have been demonstrated as effective for multiple target separations in some scenarios, the separation of equidistant sources within a single antenna beam remains a challenge. This paper presents an alternative phase tuning approach that exploits the diversity among target distances and physiological parameters for multi-target detection. The design utilizes a voltage-controlled analog phase shifter to manipulate the phase correlation of the CWDR and thus create different signal mixtures from the multiple targets, then separates them in the frequency domain by suppressing individual signals sequentially. We implemented the phase correlation system based on a 2.4 GHz single-channel CWDR and evaluated it against multiple mechanical and human targets. The experimental results demonstrated successful separation of nearly equidistant targets within an antenna beam, equivalent to separating physiological signals of two people seated shoulder to shoulder.

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Azizi, Mussyazwann Azizi Mustafa, Mohammad Nazrin Mohd Noh, Idnin Pasya, Ahmad Ihsan Mohd Yassin, and Megat Syahirul Amin Megat Ali. "Pedestrian detection using Doppler radar and LSTM neural network." IAES International Journal of Artificial Intelligence (IJ-AI) 9, no. 3 (September 1, 2020): 394. http://dx.doi.org/10.11591/ijai.v9.i3.pp394-401.

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<span lang="EN-US">Integration of radar systems as primary sensor with deep learning algorithms in driver assist systems is still limited. Its implementation would greatly help in continuous monitoring of visual blind spots from incoming pedestrians. Hence, this study proposes a single-input single-output based Doppler radar and long short-term memory (LSTM) neural network for pedestrian detection. The radar is placed in monostatic configuration at an angle of 45 degree from line of sight. Continuous wave with frequency of 1.9 GHz are continuously transmitted from the antenna. The returning signal from the approaching subjects is characterized by the branching peaks higher than the transmitted frequency. A total of 1108 spectrum traces with Doppler shifts characteristics is acquired from eight volunteers. Another 1108 spectrum traces without Doppler shifts are used for control purposes. The traces are then fed to LSTM neural network for training, validation and testing. Generally, the proposed method was able to detect pedestrian with 88.9% accuracy for training and 87.3% accuracy for testing.</span>

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5

Park, Jae-Hyun, Yeo-Jin Jeong, Ga-Eun Lee, Jun-Taek Oh, and Jong-Ryul Yang. "915-MHz Continuous-Wave Doppler Radar Sensor for Detection of Vital Signs." Electronics 8, no. 5 (May 20, 2019): 561. http://dx.doi.org/10.3390/electronics8050561.

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A miniaturized continuous-wave Doppler radar sensor operating at 915 MHz to remotely detect both respiration and heart rate (beats per minute) is presented. The proposed radar sensor comprises a front-end module including an implemented complementary metal-oxide semiconductor low-noise amplifier (LNA) and fractal-slot patch antennas, whose area was reduced by 15.2%. The two-stage inverter-based LNA was designed with an interstage capacitor and a feedback resistor to acquire ultrawide bandwidth. Two operating frequencies, 915 MHz and 2.45 GHz, were analyzed with regard to path loss for efficient operation because frequency affects detection sensitivity, reflected signal power from the human body, and measurement distance in a far-field condition. Path-loss calculation based on the simplified layer model indicates that the reflected power of the 915 MHz radar could be higher than that of the 2.45 GHz radar. The implemented radar front-end module excluding the LNA occupies 35 × 55 mm2. Vital signs were obtained via a fast Fourier transform and digital filtering using raw signals. In an experiment with six subjects, the respiration and heart rate obtained at 0.8 m using the proposed radar sensor exhibited mean accuracies of 99.4% and 97.6% with respect to commercialized reference sensors, respectively.

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6

Kyritsis, Alexandros, Rodoula Makri, and Nikolaos Uzunoglu. "Detection of Low RCS Unmanned Air Systems Using K-Band Continuous Wave Doppler Radar." Journal of Electrical and Computer Engineering 2023 (February 4, 2023): 1–13. http://dx.doi.org/10.1155/2023/5683661.

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UASs (Unmanned Air Systems) are universally used in many activities, spanning from leisure-commercial to military applications. Accordingly, as the number of UASs operating in the sky increases, so does the need to detect and identify them, in order to ensure their legitimate use. This paper introduces a continuous wave (CW) Doppler radar implementation that can be used to provide early warning for flying-by small UASs. By applying Fast Fourier Transform (FFT) to the returned signal’s Doppler frequency, estimations can be made regarding the presence of aerial bodies inside an Area of Interest (AoI). Achieving reliable detection with a low false alarm rate (FAR) while keeping the size and power demands of the system to minimum was a challenge that was successfully met. The proposed system was extensively tested in outdoor environments; measurement results are presented and parameters such as radar power, antenna gain, and noise are discussed.

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7

Choi, Byunggil, Daegun Oh, Sunwoo Kim, Jong-Wha Chong, and Ying-Chun Li. "Long-Range Drone Detection of 24 G FMCW Radar with E-plane Sectoral Horn Array." Sensors 18, no. 12 (November 28, 2018): 4171. http://dx.doi.org/10.3390/s18124171.

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In this work, a 24-GHz frequency-modulated continuous-wave (FMCW) radar system with two sectoral horn antennas and one transmitting lens antenna for long-range drone detection is presented. The present work demonstrates the detection of a quadcopter-type drone using the implemented radar system up to a distance of 1 km. Moreover, a 3D subspace-based algorithm is proposed for the joint range-azimuth-Doppler estimation of long-range drone detection. The effectiveness of the long-range drone detection is verified with the implemented radar system through a variety of experiments in outdoor environments. This is the first such demonstration for long-range drone detection with a 24-GHz FMCW radar.

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Ferrick, M. G., N. E. Yankielun, and D. F. Nelson. "A Doppler radar for continuous remote measurement of river ice velocity." Canadian Journal of Civil Engineering 23, no. 2 (April 1, 1996): 408–17. http://dx.doi.org/10.1139/l96-045.

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River ice velocity measurements are fundamental to analyses of river ice dynamics. Ice velocity measurement with a continuous-wave Doppler radar system having real-time data acquisition and digital signal processing capability was evaluated during a river breakup and a frazil run on the Connecticut River. This system can be rapidly deployed, requires minimal operator interaction, will continuously acquire, process, store, and display ice velocity data, and does not depend on visibility conditions. In parallel, video records of ice motion were obtained at the same location for later manual processing and comparison with the radar results. We describe the Doppler radar system and obtain bounding estimates of possible measurement errors. The principal error in Doppler ice velocity measurement is due to the beam width of the radar antenna, and an analytical method is developed to minimize this error. Measured ice velocities ranged from 1 to 2.5 m/s during the river breakup, and from 0.5 to 0.65 m/s in the frazil run. Quantitative comparisons between the radar and video results show fundamental agreement between these measurement methods, and demonstrate that Doppler radar is an effective, efficient, and precise tool for obtaining river ice velocities over the full range of possible ice and velocity conditions. Key words: Doppler radar, river ice velocity, velocity measurement, error analysis, river breakup, frazil run.

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9

Gouveia, Carolina, José Vieira, and Pedro Pinho. "A Review on Methods for Random Motion Detection and Compensation in Bio-Radar Systems." Sensors 19, no. 3 (January 31, 2019): 604. http://dx.doi.org/10.3390/s19030604.

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The bio-radar system can measure vital signals accurately, by using the Doppler effect principle, which relates the received signal properties to the distance change between the radar antennas and the subject chest-wall. These systems have countless applications, from short range detection to assist in rescue missions, to long-term applications as for the continuous sleeping monitoring. Once the main applications of these systems intend to monitor subjects during long periods of time and under noisy environments, it is impossible to guarantee the patient immobilization, hence its random motion, as well as other clutter sources, will interfere in the acquired signals. Therefore, the signal processing algorithms developed for these applications have been facing several challenges regarding the random motion detection and mitigation. In this paper, an extended review on the already implemented methods is done, considering continuous wave radars. Several sources of random motion are considered, along with different approaches to compensate the distortions caused by them.

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10

Arab, Homa, Steven Dufour, Emilia Moldovan, Cevdet Akyel, and Serioja Tatu. "A 77-GHz Six-Port Sensor for Accurate Near-Field Displacement and Doppler Measurements." Sensors 18, no. 8 (August 6, 2018): 2565. http://dx.doi.org/10.3390/s18082565.

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A continuous-wave (CW) radar sensor design based on a millimetre-wave six-port interferometer is proposed. A complete sensor prototype is conceived of, fabricated and measured at 77 GHz for short-range professional and industrial applications. This sensor is designed to measure distances and Doppler frequencies with high accuracy, at a reasonable cost. Accurate phase measurements are also performed using the six-port technology, which makes it a promising candidate for CW radar sensing applications. Advances in the performance and functionality of six-port sensors are surveyed to highlight recent progress in this area. These include improvements in design, low power consumption, high signal to noise ratio, compactness, robustness and simplicity in realization. Given the fact that they are easy to fabricate, due to the lack of active circuits and being highly accurate, it is expected that six-port sensors will significantly contribute to the development of human tracking devices and industrial sensors in the near future. The entire circuit prototype, including the transmitter, the receiver antenna, the six-port interferometer and the four power detectors have been integrated on a die. The circuit is fabricated using a hybrid integrated technology on a 127-μm ceramic substrate with a relative permittivity of εr=9.8. Calibrated tuning forks are used to assess the performance of the six-port sensor experimentally for various frequencies.

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11

Hyun, Eugin, Young-Seok Jin, Jae-Hyun Park, and Jong-Ryul Yang. "Machine Learning-Based Human Recognition Scheme Using a Doppler Radar Sensor for In-Vehicle Applications." Sensors 20, no. 21 (October 30, 2020): 6202. http://dx.doi.org/10.3390/s20216202.

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In this paper, we propose a Doppler spectrum-based passenger detection scheme for a CW (Continuous Wave) radar sensor in vehicle applications. First, we design two new features, referred to as an ‘extended degree of scattering points’ and a ‘different degree of scattering points’ to represent the characteristics of the non-rigid motion of a moving human in a vehicle. We also design one newly defined feature referred to as the ‘presence of vital signs’, which is related to extracting the Doppler frequency of chest movements due to breathing. Additionally, we use a BDT (Binary Decision Tree) for machine learning during the training and test steps with these three extracted features. We used a 2.45 GHz CW radar front-end module with a single receive antenna and a real-time data acquisition module. Moreover, we built a test-bed with a structure similar to that of an actual vehicle interior. With the test-bed, we measured radar signals in various scenarios. We then repeatedly assessed the classification accuracy and classification error rate using the proposed algorithm with the BDT. We found an average classification accuracy rate of 98.6% for a human with or without motion.

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12

Hyun, Eugin, Young-Seok Jin, and Jong-Hun Lee. "Design and Implementation of 24 GHz Multichannel FMCW Surveillance Radar with a Software-Reconfigurable Baseband." Journal of Sensors 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/3148237.

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We designed and developed a 24 GHz surveillance FMCW (Frequency Modulated Continuous Wave) radar with a software-reconfigurable baseband. The developed radar system consists of transceiver, two selectable transmit antennas, eight parallel receive antennas, and a back-end module for data logging and to control the transceiver. The architecture of the developed radar system can support various waveforms, gain control of receive amplifiers, and allow the selection of two transmit antennas. To do this, we implemented the transceiver using a frequency synthesizer device and a two-step VGA (Variable Gain Amplifier) along with switch-controlled transmit antennas. To support high speed implementation features along with good flexibility, we developed a back-end module based on a FPGA (Field Programmable Gate Array) with a parallel architecture for the real-time data logging of the beat signals received from a multichannel 24 GHz transceiver. To verify the feasibility of the developed radar system, signal processing algorithms were implemented on a host PC. All measurements were carried out in an anechoic chamber to extract a 3D range-Doppler-angle map and target detections. We expect that the developed software-reconfigurable radar system will be useful in various surveillance applications.

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13

Kim, Heesoo, and Jinho Jeong. "Non-Contact Measurement of Human Respiration and Heartbeat Using W-band Doppler Radar Sensor." Sensors 20, no. 18 (September 12, 2020): 5209. http://dx.doi.org/10.3390/s20185209.

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This paper presents a W-band continuous-wave (CW) Doppler radar sensor for non-contact measurement of human respiration and heartbeat. The very short wavelength of the W-band signal allows a high-precision detection of the displacement of the chest surface by the heartbeat as well as respiration. The CW signal at 94 GHz is transmitted through a high-gain horn antenna to the human chest at a distance of 1 m. The phase-modulated reflection signal is down-converted to the baseband by the quadrature mixer with an excellent amplitude and phase matches between I and Q channels, which makes the IQ mismatch correction in the digital domain unnecessary. The baseband I and Q data are digitized using data acquisition (DAQ) board. The arctangent demodulation with automatic phase unwrapping is applied to the low-pass filtered I and Q data to effectively solve the null point problem. A slow-varying DC component is rejected in the demodulated signal by the trend removal algorithm. Then, the respiration signal with a frequency of 0.27 Hz and a displacement of ~6.1 mm is retrieved by applying a low-pass filter. Finally, the respiration signal is removed by the band-pass filter and the heartbeat signal is extracted, showing a frequency of 1.35 Hz and a displacement of ~0.26 mm. The extracted respiration and heartbeat rates are very close to the manual measurement results. The demonstrated W-band CW radar sensors can be easily applied to find the angular location of the human body by using a phased array under a compact size.

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Zhao, Yanhua, Vladica Sark, Milos Krstic, and Eckhard Grass. "Low Complexity Radar Gesture Recognition Using Synthetic Training Data." Sensors 23, no. 1 (December 28, 2022): 308. http://dx.doi.org/10.3390/s23010308.

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Developments in radio detection and ranging (radar) technology have made hand gesture recognition feasible. In heat map-based gesture recognition, feature images have a large size and require complex neural networks to extract information. Machine learning methods typically require large amounts of data and collecting hand gestures with radar is time- and energy-consuming. Therefore, a low computational complexity algorithm for hand gesture recognition based on a frequency-modulated continuous-wave (FMCW) radar and a synthetic hand gesture feature generator are proposed. In the low computational complexity algorithm, two-dimensional Fast Fourier Transform is implemented on the radar raw data to generate a range-Doppler matrix. After that, background modelling is applied to separate the dynamic object and the static background. Then a bin with the highest magnitude in the range-Doppler matrix is selected to locate the target and obtain its range and velocity. The bins at this location along the dimension of the antenna can be utilised to calculate the angle of the target using Fourier beam steering. In the synthetic generator, the Blender software is used to generate different hand gestures and trajectories and then the range, velocity and angle of targets are extracted directly from the trajectory. The experimental results demonstrate that the average recognition accuracy of the model on the test set can reach 89.13% when the synthetic data are used as the training set and the real data are used as the test set. This indicates that the generation of synthetic data can make a meaningful contribution in the pre-training phase.

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15

Tang, Taiwen, Chen Wu, and Janaka Elangage. "Analyze the FMCW Waveform Skin Return of Moving Objects in the Presence of Stationary Hidden Objects Using Numerical Models." Electronics 10, no. 1 (December 28, 2020): 28. http://dx.doi.org/10.3390/electronics10010028.

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In this paper, a high-performance antenna array system model is presented to analyze moving-object-skin-returns and track them in the presence of stationary objects using frequency modulated continuous wave (FMCW). The main features of the paper are bonding the aspects of antenna array and electromagnetic (EM) wave multi-skin-return modeling and simulation (M&S) with the aspects of algorithm and measurement/tracking system architecture. The M&S aspect models both phase and amplitude of the signal waveform from a transmitter to the signal processing in a receiver. In the algorithm aspect, a novel scheme for FMCW signal processing is introduced by combining time- and frequency-domain methods, including a vector moving target indication filter and a vector direct current canceller in time-domain, and a constant false alarm rate detector and a mono-pulse digital beamforming angle tracker in frequency-domain. In addition, unlike previous designs of using M × N fast Fourier transform (FFT) for an M × N array, only four FFTs are used, which tremendously save time and space in hardware. With the presented model, the detection of the moving-target-skin-return in stationary objects under a noisy environment is feasible. Therefore, to track long range and high-speed objects, the proposed technique is promising. Using a scenario having (1) a target with 17 dBm2 radar cross section (RCS) at about 40 km range with 5.936 Mach speed and 11.6 dB post processing signal to noise ratio, and (2) a strong stationary clutter with 37 dBm2 RCS located at the proximity of the target, it demonstrates that the root-mean-square errors of range, angle, and Doppler measurements are about 26 m, 0.68 degree, and 1100 Hz, respectively.

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Sun, Weifeng, Zhenzhen Pang, Weimin Huang, Peng Ma, Yonggang Ji, Yongshou Dai, and Xiaotong Li. "A Multi-Stage Vessel Tracklet Association Method for Compact High-Frequency Surface Wave Radar." Remote Sensing 14, no. 7 (March 26, 2022): 1601. http://dx.doi.org/10.3390/rs14071601.

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A compact high-frequency surface wave radar, used for target detection, suffers from a low signal-to-noise ratio, low detection probability, a high false alarm rate, and low positioning accuracy; this is due to its low transmit power and the reduced aperture size of the receiving antenna array. When target tracking algorithms are applied to compact high-frequency surface wave radar data, track fragmentation often occurs and a long track may be broken into several track segments (a.k.a. tracklets), which degrade the tracking continuity for a maritime surveillance system. We present a multi-stage vessel tracklet association method, based on bidirectional prediction and optimal assignment, to associate the broken tracklets belonging to the same target, and connect them to form one continuous track in a multi-target tracking scenario. Firstly, two global motion parameters, i.e., the average heading and average speed, were, respectively, extracted from the newly initiated and terminated tracklets as features for a rough tracklet association, then k-means clustering was used to produce the preliminary tracklet pairs. Subsequently, the temporal and spatial constraints on the initiated and terminated tracklets were considered to refine the preliminary tracklet pairs, to obtain the candidate tracklet pairs. Finally, the tracklet association costs were calculated using Doppler velocity, range, and azimuth to determine the similarity between tracklets in the candidate tracklet pairs, and an association cost matrix was obtained. Then an optimal assignment method based on Jonker–Volgenant–Castanon algorithm was applied to the association matrix to achieve optimal tracklet matching by minimizing the total association costs. Tracklet association experiments with both simulated and field data were conducted; experimental results show that, compared with existing track segment association methods, the association accuracy of the proposed method is significantly improved with better tracking continuity.

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17

Miclăuş, S., D. Vatamanu, R. Mitran, and C. Neghină. "Microwaves propagation through a small fire curtain at 3.55 GHz and 6.26 GHz and the impact on vital signs detection by using a four-element patch antenna array." IOP Conference Series: Materials Science and Engineering 1254, no. 1 (September 1, 2022): 012010. http://dx.doi.org/10.1088/1757-899x/1254/1/012010.

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Abstract The impact of the presence of a fire curtain not wider than 7 cm on an air path 150 cm long of two continuous waves at frequencies of 3.55 GHz and 6.26 GHz was quantified. Two identical patch array antennas with four linear elements were used at emission and reception and they were designed and characterized specifically for this purpose. The magnitude and phase of the transmission coefficient were measured by a vector network analyzer in all the experimental sessions. Comparing the air path and the air-plus-fire path of the waves, it resulted that fire induced shifts in magnitude and phase that depended on frequency and on the experimental setup. The heating of the antenna could have contributed to the overall observed effects. The detection of the human heartbeat by Doppler radar technique was not much influenced by the presence of fire, but the amplitude of the detected beats was increased. The array antennas produced noisy signals for the vital sign detection and the origin of this behaviour was hypothesized.

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18

Cardullo, Paul A. "Continuous-Wave Doppler Ultrasound." Journal for Vascular Ultrasound 35, no. 4 (December 2011): 201–7. http://dx.doi.org/10.1177/154431671103500403.

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19

Liang, Haidong-Dong, Chun Sing Louis Tsui, Michael Halliwell, and Peter N. T. Wells. "Continuous wave ultrasonic Doppler tomography." Interface Focus 1, no. 4 (June 2011): 665–72. http://dx.doi.org/10.1098/rsfs.2011.0018.

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In continuous wave ultrasonic Doppler tomography (DT), the ultrasonic beam moves relative to the scanned object to acquire Doppler-shifted frequency spectra which correspond to cross-range projections of the scattering and reflecting structures within the object. The relative motion can be circular or linear. These data are then backprojected to reconstruct the two-dimensional image of the object cross section. By using coherent processing, the spatial resolution of ultrasonic DT is close to an order of magnitude better than that of traditional pulse-echo imaging at the same ultrasound frequency.

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20

Chrisman, Jolinda, Spencer Warren, and Charlotte Davis. "Conquering the continuous wave venous Doppler." Nursing Made Incredibly Easy! 10, no. 5 (2012): 51–53. http://dx.doi.org/10.1097/01.nme.0000418043.89012.43.

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21

Long, James W., Russell Stevens, Edgar Lichti, and Donald Silver. "Reliability of continuous-wave Doppler probes." Journal of Vascular Surgery 5, no. 4 (April 1987): 558–65. http://dx.doi.org/10.1067/mva.1987.avs0050558.

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22

Enseleit, Frank, Ivan Reho, Thomas Largiadèr, and Rolf Jenni. "Continuous Wave Doppler Signal: A Mystery." Journal of the American Society of Echocardiography 19, no. 9 (September 2006): 1191.e1–1191.e3. http://dx.doi.org/10.1016/j.echo.2006.05.003.

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23

Long, James W., Russell Stevens, Edgar Lichti, and Donald Silver. "Reliability of continuous-wave Doppler probes." Journal of Vascular Surgery 5, no. 4 (April 1987): 558–65. http://dx.doi.org/10.1016/0741-5214(87)90220-5.

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24

Poe, Patricia. "Lower-Extremity Arterial Continuous-Wave Doppler Evaluation." Journal for Vascular Ultrasound 36, no. 2 (June 2012): 123–34. http://dx.doi.org/10.1177/154431671203600205.

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25

Harris, Michael, Graham Constant, and Carol Ward. "Continuous-wave bistatic laser Doppler wind sensor." Applied Optics 40, no. 9 (March 20, 2001): 1501. http://dx.doi.org/10.1364/ao.40.001501.

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26

Callahan, Mark J. "Doppler Echocardiography: Quantitative Methods of Pulsed and Continuous Wave Cardiac Doppler." Mayo Clinic Proceedings 61, no. 8 (August 1986): 682–83. http://dx.doi.org/10.1016/s0025-6196(12)62047-3.

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27

Martin, James F. "Doppler Echocardiography: Quantitative Methods of Pulsed and Continuous Wave Cardiac Doppler." Radiology 160, no. 2 (August 1986): 520. http://dx.doi.org/10.1148/radiology.160.2.520.

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28

Tehan, Peta Ellen, Mathew Sebastian, Alex Louise Barwick, and Vivienne Helaine Chuter. "How sensitive and specific is continuous-wave Doppler for detecting peripheral arterial disease in people with and without diabetes? A cross-sectional study." Diabetes and Vascular Disease Research 15, no. 5 (June 20, 2018): 396–401. http://dx.doi.org/10.1177/1479164118782887.

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Background: Continuous-wave Doppler is frequently used for detecting peripheral arterial disease in patients with diabetes; however, there is limited evidence investigating diagnostic accuracy. This study aimed to determine sensitivity and specificity of continuous-wave Doppler for detecting peripheral arterial disease in populations with, and without, diabetes and to investigate the influence of disease severity on sensitivity of continuous-wave Doppler for detecting peripheral arterial disease. Results: Data from 396 participants were included. Using colour Duplex ultrasound as reference standard (N=66), printed continuous-wave Doppler waveform analysis sensitivity was 81.75% (95% confidence interval: 76.75 to 85.88) and specificity 89.34% (95% confidence interval: 82.62 to 93.67). Printed continuous-wave Doppler waveform analysis sensitivity for peripheral arterial disease was comparable to sensitivity calculated using angiography as the reference standard (81.67%; 95% confidence interval: 69.56 to 90.48). Sensitivity and specificity were unaffected by diabetes diagnosis (n = 176), sensitivity 82.76% (95% confidence interval: 74.86 to 88.55), and specificity 88.33% (95% confidence interval: 77.82 to 94.23). Conclusion: Continuous-wave Doppler is a fair assessment tool for peripheral arterial disease in a community-based sample with suspected peripheral arterial disease. Diagnostic accuracy of continuous-wave Doppler for peripheral arterial disease is unaffected by the presence of diabetes.

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Harward, T. R. S., K. Kraemer, E. F. Bernstein, and A. Fronek. "Objective Quantification of the Continuous-Wave Venous Doppler Examination." Phlebology: The Journal of Venous Disease 11, no. 2 (June 1996): 62–67. http://dx.doi.org/10.1177/026835559601100207.

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Objective: To develop a quantitative, objective method to diagnose deep venous thrombosis (DVT) with the continuous-wave (CW) Doppler system. Design: Case control study. Setting: Vascular Laboratory of the Surgical Services, Veteran's Affairs Medical Center, La Jolla, California, USA. Patients, participants: Thirty-five control subjects and the limbs of 50 patients with suspected DVT were examined. Main outcome measures: Phlebography, CW Doppler ultrasound. CW Doppler output was recorded from the popliteal, superficial femoral and common femoral veins. The response to standardized calf compression was analysed. Results: The most useful information included the Doppler velocity increase, decay time and deceleration. Because the determination of decay time does not require calibration of the Doppler system, it is the preferred parameter. Conclusions: A decay time longer than 1.05 s is a very good discriminant between normal control and DVT limbs.

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30

Xiong Jiuliang, 熊久良, 武占成 Wu Zhancheng, 孙永卫 Sun Yongwei, 杨清熙 Yang Qingxi, 程二威 Cheng Erwei, and 王琳 Wang Lin. "LEMP irradiation effects on continuous wave Doppler fuze." High Power Laser and Particle Beams 27, no. 4 (2015): 43203. http://dx.doi.org/10.3788/hplpb20152704.43203.

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ALY, MOHSEN. "STABILITY ANALYSIS OF PASSIVE CONTINUOUS-WAVE DOPPLER SEEKERS." International Conference on Aerospace Sciences and Aviation Technology 5, ASAT CONFERENCE (May 1, 1993): 1–7. http://dx.doi.org/10.21608/asat.1993.25632.

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32

Madjar, H. "Breast examinations with continuous wave and color Doppler." Ultrasound in Obstetrics and Gynecology 2, no. 3 (May 1, 1992): 215–20. http://dx.doi.org/10.1046/j.1469-0705.1992.02030215.x.

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Katz, William E., Thomas A. Gasior, Joseph J. Quinlan, and John Gorcsan. "Transgastric continuous-wave Doppler to determine cardiac output." American Journal of Cardiology 71, no. 10 (April 1993): 853–57. http://dx.doi.org/10.1016/0002-9149(93)90836-2.

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34

Smallwood, R. H., and P. Dixon. "An electronic Doppler signal generator for assessing continuous-wave ultrasonic Doppler flowmeters." IEE Proceedings A Physical Science, Measurement and Instrumentation, Management and Education, Reviews 133, no. 2 (1986): 104. http://dx.doi.org/10.1049/ip-a-1.1986.0017.

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35

Demoz, Belay, Cyrille Flamant, Tammy Weckwerth, David Whiteman, Keith Evans, Frédéric Fabry, Paolo Di Girolamo, et al. "The Dryline on 22 May 2002 during IHOP_2002: Convective-Scale Measurements at the Profiling Site." Monthly Weather Review 134, no. 1 (January 1, 2006): 294–310. http://dx.doi.org/10.1175/mwr3054.1.

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Abstract A detailed analysis of the structure of a double dryline observed over the Oklahoma panhandle during the first International H2O Project (IHOP_2002) convective initiation (CI) mission on 22 May 2002 is presented. A unique and unprecedented set of high temporal and spatial resolution measurements of water vapor mixing ratio, wind, and boundary layer structure parameters were acquired using the National Aeronautics and Space Administration (NASA) scanning Raman lidar (SRL), the Goddard Lidar Observatory for Winds (GLOW), and the Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE), respectively. These measurements are combined with the vertical velocity measurements derived from the National Center for Atmospheric Research (NCAR) Multiple Antenna Profiler Radar (MAPR) and radar structure function from the high-resolution University of Massachusetts frequency-modulated continuous-wave (FMCW) radar to reveal the evolution and structure of the late afternoon double-dryline boundary layer. The eastern dryline advanced and then retreated over the Homestead profiling site in the Oklahoma panhandle, providing conditions ripe for a detailed observation of the small-scale variability within the boundary layer and the dryline. In situ aircraft data, dropsonde and radiosonde data, along with NCAR S-band dual-polarization Doppler radar (S-Pol) measurements, are also used to provide the larger-scale picture of the double-dryline environment. Moisture and temperature jumps of about 3 g kg−1 and 1–2 K, respectively, were observed across the eastern radar fine line (dryline), more than the moisture jumps (1–2 g kg−1) observed across the western radar fine line (secondary dryline). Most updraft plumes observed were located on the moist side of the eastern dryline with vertical velocities exceeding 3 m s−1 and variable horizontal widths of 2–5 km, although some were as wide as 7–8 km. These updrafts were up to 1.5 g kg−1 moister than the surrounding environment. Although models suggested deep convection over the Oklahoma panhandle and several cloud lines were observed near the dryline, the dryline itself did not initiate any storms over the intensive observation region (IOR). Possible reasons for this lack of convection are discussed. Strong capping inversion and moisture detrainment between the lifting condensation level and the level of free convection related to an overriding drier air, together with the relatively small near-surface moisture values (less than 10 g kg−1), were detrimental to CI in this case.

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Queißer, Manuel, Michael Harris, and Steven Knoop. "Atmospheric visibility inferred from continuous-wave Doppler wind lidar." Atmospheric Measurement Techniques 15, no. 18 (September 29, 2022): 5527–44. http://dx.doi.org/10.5194/amt-15-5527-2022.

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Abstract. Atmospheric visibility, or meteorological optical range (MOR), is governed by light extinction by aerosols. State-of-the-art visibility sensors, such as employed in meteorological observatories and airports, infer MOR by measuring either transmittance or scattering. While these sensors yield robust measurements with reasonable accuracy (10 % to 20 %), they measure in situ. MOR from these sensors may thus not be representative of MOR further away, for example, under conditions with stratified aerosol types. This includes off-shore sites near the sea surface during conditions with advection fog, sea spray or mist. Elastic backscatter lidar can be used to measure light extinction and has previously demonstrated to be a powerful method to infer visibility. Lidar can measure visibility not just near the instrument but also further away (remotely) and single-ended whilst also being capable of measuring profiles of MOR along atmospheric slant paths. Continuous-wave (CW) Doppler wind lidar systems make up one of the most widespread type of elastic backscatter lidar and are typically used in wind resource assessment. Using these existing platforms for remote and single-ended measurement of MOR profiles could allow for new and valuable applications. However, the low-light extinction associated with this type of lidar excludes the use of the extinction coefficient for MOR retrieval but leaves the backscatter coefficient as a possible proxy for MOR, though with an accuracy expected to be inferior to the former method. We analysed backscatter data from CW wind lidar and co-measured MOR from visibility sensors from two campaigns (Cabauw, Netherlands, and Pershore, United Kingdom) and found backscatter from CW wind lidar to be a viable proxy of MOR if calibrated against a visibility sensor. The expected accuracy of the method is low and of the order of few kilometres. This means MOR from CW wind lidar could be used in safety-uncritical problems, such as assessment of visibility of manmade objects, including wind turbines.

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Amemiya, Shin‐ichi, and Kenji Ishiwata. "Ultrasonic continuous wave blood flowmeter using Doppler effect analysis." Journal of the Acoustical Society of America 89, no. 1 (January 1991): 493. http://dx.doi.org/10.1121/1.400396.

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38

Couture, Etienne J., Alexander S. Kuo, Michael N. Andrawes, and Michael G. Fitzsimons. "Double Envelope on Continuous Wave Mitral Inflow Doppler Profile." Journal of Cardiothoracic and Vascular Anesthesia 33, no. 11 (November 2019): 3222–23. http://dx.doi.org/10.1053/j.jvca.2019.05.049.

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39

Cobey, Frederick C., and Swapnil Khoche. "Double Envelope With Continuous Wave Doppler: Not an Artifact." Journal of Cardiothoracic and Vascular Anesthesia 33, no. 11 (November 2019): 3223–27. http://dx.doi.org/10.1053/j.jvca.2019.05.050.

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40

Alwi, M., Z. A. A. Hamid, and R. Zambahari. "A characteristic continuous wave Doppler signal in cor triatriatum?" Heart 68, no. 7 (July 1, 1992): 6–8. http://dx.doi.org/10.1136/hrt.68.7.6.

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41

Glaser, J. "A characteristic continuous wave Doppler signal in cor triatriatum?" Heart 69, no. 5 (May 1, 1993): 470. http://dx.doi.org/10.1136/hrt.69.5.470.

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42

Guntheroth, Warren G. "High frequency pulsed versus continuous wave Doppler echocardiography (continued)." Journal of the American College of Cardiology 9, no. 3 (March 1987): 704. http://dx.doi.org/10.1016/s0735-1097(87)80068-2.

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43

Teague, Steve M., James A. Heinsimer, Jerome L. Anderson, Kevin Sublett, Edwin G. Olson, Wyatt F. Voyles, and Udho Thadani. "Quantification of aortic regurgitation utilizing continuous wave Doppler ultrasound." Journal of the American College of Cardiology 8, no. 3 (September 1986): 592–99. http://dx.doi.org/10.1016/s0735-1097(86)80188-7.

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44

Come, Patricia C. "The optimal doppler examination: Pulsed, continuous wave or both?" Journal of the American College of Cardiology 7, no. 4 (April 1986): 886–88. http://dx.doi.org/10.1016/s0735-1097(86)80352-7.

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45

Gorcsan, John, Paul Diana, Beth A. Ball, and Brack G. Hattler. "Determination of cardiac output by transesophaogal continuous wave Doppler." Journal of the American College of Cardiology 17, no. 2 (February 1991): A262. http://dx.doi.org/10.1016/0735-1097(91)92013-c.

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46

Gorcsan, John, William M. Kenny, Paul Diana, Kenneth A. Bernhard, and Gary C. Marrone. "Transesophageal continuous-wave Doppler to evaluate mitral prosthetic stenosis." American Heart Journal 121, no. 3 (March 1991): 911–14. http://dx.doi.org/10.1016/0002-8703(91)90209-z.

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47

Rush, Michael, Martin Thomas, Jack Zyroff, David McNally, Mary Rossman, Shirley Duren, and Shirley Otis. "Duplex scanning with continuous wave doppler for carotid disease." Journal of Clinical Ultrasound 13, no. 5 (June 1985): 325–28. http://dx.doi.org/10.1002/jcu.1870130505.

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48

Branlard, E., A. T. Pedersen, J. Mann, N. Angelou, A. Fischer, T. Mikkelsen, M. Harris, C. Slinger, and B. F. Montes. "Retrieving wind statistics from average spectrum of continuous-wave lidar." Atmospheric Measurement Techniques Discussions 6, no. 1 (February 19, 2013): 1943–77. http://dx.doi.org/10.5194/amtd-6-1943-2013.

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Abstract. The aim of this study is to experimentally demonstrate that the time-average Doppler spectrum of a continuous-wave lidar is proportional to the probability density function of the line-of-sight velocities. This would open the possibility of using cw lidars for a precise determination of the second-order atmospheric turbulence statistics. An atmospheric field campaign and a wind tunnel experiment are carried out to show that the use of an average Doppler spectrum instead of a time series of velocities determined from individual Doppler spectra significantly reduces the differences with the standard deviation measured using ordinary anemometers, such as ultra-sonic anemometers or hotwires. The proposed method essentially removes the spatial averaging effect intrinsic to the cw lidar systems.

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Branlard, E., A. T. Pedersen, J. Mann, N. Angelou, A. Fischer, T. Mikkelsen, M. Harris, C. Slinger, and B. F. Montes. "Retrieving wind statistics from average spectrum of continuous-wave lidar." Atmospheric Measurement Techniques 6, no. 7 (July 15, 2013): 1673–83. http://dx.doi.org/10.5194/amt-6-1673-2013.

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Abstract. The aim of this study is to experimentally demonstrate that the time-average Doppler spectrum of a continuous-wave (cw) lidar is proportional to the probability density function of the line-of-sight velocities. This would open the possibility of using cw lidars for the determination of the second-order atmospheric turbulence statistics. An atmospheric field campaign and a wind tunnel experiment are carried out to show that the use of an average Doppler spectrum instead of a time series of velocities determined from individual Doppler spectra significantly reduces the differences with the standard deviation measured using ordinary anemometers, such as ultra-sonic anemometers or hotwires. The proposed method essentially removes the spatial averaging effect intrinsic to the cw lidar systems.

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WILKENSHOFF, U. M., I. KRUCK, D. GAST, and R. SCHRÖDER. "Validity of continuous wave Doppler and colour Doppler in the assessment of aortic regurgitation." European Heart Journal 15, no. 9 (September 1994): 1227–34. http://dx.doi.org/10.1093/oxfordjournals.eurheartj.a060657.

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