STUDY OF PULSED DOPPLER SIGNAL PROCESSING AND VELOCITY TRACKING TECHNIQUE

This paper describes a signal processing system in a Pulsed Doppler (PD) radar. It mainly consists of a velocity tracking loop and a digital signal processing auxiliary channel. With many signal processing techniques, the system successfully solves the signal detection and tracking at low SNR and the interference identification and rejection. The idea of system design is introduced in detail. Finally, some simulation and experimental results are presented.

Prevalence of Atrial Fibrillation in Systolic Heart Failure, Pulsed and Tissue Doppler Echocardiographic Abnormalities

Background: Heart failure (HF) is a common clinical syndrome mostly due to the impaired ability of the Left Ventricle (LV) to eject blood with reduced cardiac output. Heart failure is called systolic (SHF) if left ventricle ejection fraction on echo-cardiogram is low (LVEF of ≤50%). Aim: To assess the echocardiographic characteristics of patients with SHF with Atrial Fibrillation (AF) and compare with those with Sinus Rhythm (SR) on 12 leads ECG. Furthermore, to evaluate the clinical and biochemical markers for the prediction of AF in SHF. Method: Over two years duration, each patient diagnosed with SHF was enrolled in the study (n = 354) based on admission code. AF or sinus rhythm on 12 leads ECG was documented on each patient. Multiple logistic regression analysis was applied to assess the risk ratio of different clinical and Doppler derived variables for the development of AF in SHF. Results: Out of the total hospital medical admissions of 14,674 patients, there were 354 patients with diagnosis of SHF, a prevalence of 2.4%. The incidence of AF on ECG was 109 (31%) patients in the whole study population and 245 (69%) in SR. M Mode echocardiogram in patients with SHF and AF compared with those in SR showed significant dilation of LV cavity in systole with LVESD of 5.72 ± 0.63 vs. 5.23 ± 0.76 cm, P < 0.001 and in Diastole LVEDD of 6.83 ± 0.51 vs. 6.58 ± 0.63 cm, P < 0.001. Pulsed Doppler echocardiogram showed a severe restrictive-pattern with shorter Decellration Time (DT) of 163.73 ± 7.42 vs. 214.9 ± 31.81msec, P < 0.001 and higher Pulse to Tissue Doppler ratio of E/Em of 14.26 ± 1.34 vs. 9.99 ± 1.27, P , and the serum level of Brain Natriuretic Peptide (BNP) hormone of 723.72 ± 13.45 vs. 686.98 ± 72.57 pg/ml, P < 0.001. The predictive risks (odd ratio) of different clinical variables for the development of AF in SHF were positive for high BNP > 500 pg/ml of 2.8, history of hypertension of 1.8, history of DM of 1.7, BMI > 28 of 1.4, LV hypertrophy on ECG of 1.3. Conclusions: The prevalence of Systolic Heart Failure in the study population was 2.4%. The prevalence of AF in the study population was 31%. The best predictors of AF in SHF were high BNP > 500 pg/ml, history of hypertension, Diabete Mellitus and LV Hypertrophy on ECG.

Study on the method of polarization suppression of cheating jamming in pulse Doppler radar

A jamming suppression method based on polarization signal detection is proposed under common range and velocity cheating jammingfor pulse Doppler radar. On the basis of the separation of the target and the jamming, the range and velocity track on the true target are realized. Firstly the signal processing model of the full polarization pulse Doppler radar is introduced. Secondly the method of correct target separation is discussed, which is the twice detections of energy and polarization state on the two dimension resolution cells of range and velocity of the radar echo. Finally the simulations are performed and the results prove the validity. What's more, multiple range and velocity cheating jamming can be suppressed at the same time if the target and the jamming are different in the polarization domain.

Repeater jamming suppression method for pulse Doppler fuze based on identity recognition and chaotic encryption

Pulse Doppler(PD) fuze is widely used in current battlefield. However, with the threat of repeater jamming, especially digital radio frequency memory technology, the deficiency in the anti-repeater jamming of a traditional PD fuze increasingly emerges. Therefore, a repeater jamming suppression method for a PD fuze based on identity(ID) recognition and chaotic encryption is proposed. Every fuze has its own ID which is encrypted with different chaotic binary sequences in every pulse period of the transmitted signal. The thumbtack-shaped ambiguity function shows a good resolution and distance cutoff characteristic. The ability of anti-repeater jamming is emphatically analyzed, and the results at different signal-to-noise ratio(SNR) show a strong anti-repeater jamming ability and range resolution that the proposed method possesses. Furthermore, the anti-repeater jamming ability is influenced by processing gain, bit error rate(BER) and correlation function. The simulation result validates the theoretical analysis, it shows the proposed method can significantly improve the anti-repeater jamming ability of a PD fuze.

Adaptive target and jamming recognition for the pulse doppler radar fuze based on a time-frequency joint feature and an online-updated naive bayesian classifier with minimal risk

This paper considers the problem of target and jamming recognition for the pulse Doppler radar fuze(PDRF).To solve the problem,the matched filter outputs of the PDRF under the action of target and jamming are analyzed.Then,the frequency entropy and peak-to-peak ratio are extracted from the matched filter output of the PDRF,and the time-frequency joint feature is constructed.Based on the time-frequency joint feature,the naive Bayesian classifier(NBC)with minimal risk is established for target and jamming recognition.To improve the adaptability of the proposed method in complex environments,an online update process that adaptively modifies the classifier in the duration of the work of the PDRF is proposed.The experiments show that the PDRF can maintain high recognition accuracy when the signal-to-noise ratio(SNR)decreases and the jamming-to-signal ratio(JSR)increases.Moreover,the applicable analysis shows that he ONBCMR method has low computational complexity and can fully meet the real-time requirements of PDRF.

Computer simulation studies of pulsed Doppler signals from vortices

A computer simulation method for pulsed Doppler signals from vortices was pro- posed to generate simulated vortex Doppler signals under various given circumstances. The relative waveforms, such as the maximum frequency waveform, the mean frequency waveform and the bandwidth waveform, were obtained using the short time Fourier analysis of those simulated signals. The relations were studied between several spectrum parameters obtained from these waveforms and given simulation conditions, such as the position and the size of the sample volume, the distance between two vortices, the free stream velocity and the maximum tangent velocity of the vortex. The sensitive parameters were found to detect vortices using the pulsed Doppler techniques.

SEVERAL PROBLEMS IN DESIGNING DBS SYSTEMS FOR AIRBORNE PULSE DOPPLER RADAR

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QUANTITATIVE ANALYSIS ON CHANGES OF HEPATIC HEMODYNAMICS AFTER TRANSCUTANEOUS ELECTRIC PULSE STIMULATION OF LOCAL POINTS BY USING COLOR DOPPLER ULTRASOUND DIAGNOSTIC APPARATUS

Objective: To evaluate the effect of transcutaneous electric pulse stimulation (TEPS) on hepatic blood flow and parenchymal microcirculation in patients with fatty liver. Methods: A total of 31 fatty liver volunteer patients were observed in this study. Changes of color Doppler energy (CDE) images before and after TEPS of local points nearby the liver were recorded by using color Doppler ultrasound diagnostic apparatus (ACUSON 128XP/10C). Sum of color pixel area (SCPA), average of color value (ACV) and SCPA×ACV (integral) of the hepatic flow images were analyzed by an image processing system, single blind method and paired t-test. Programmed TEPS (0.5- 150 Hz / 2 000 Hz , 10- 25 V ) was applied to the right Qimen (期门 LR 14)-Jingmen (京门 GB 25), Fuai (腹哀 SP 16)-Ganshu (肝俞 BL 18) respectively for 15 min. Results: Compared with basic values of pretreatment, SCPA, ACV and SCPA×ACV increased significantly (t=2.71, P<0.02; t=3.42, P<0.01; and t=8.15, P<0.001) after TEPS, meaning improvement of hepatic blood flow supply. Conclusion: TEPS of acupoints near the liver can improve hepatic blood flow and hepatic parenchymal microcirculation in patients with fatty liver.

Pulse wave Doppler ultrasound of testicular arteries and their relationship with semen characteristics in healthy bulls

Background: Semen evaluation is used to estimate the testicular function. In bulls, the spermatozoa present in the ejaculate are the result of a process that begun more than 2 mo earlier, bequeathing a delayed depiction of the actual function of the testis. Since testis vascularization might be critical for the gonad function, selected pulse wave Doppler ultrasound parameters were assessed in this study, for instance the peak systolic velocity, the end diastolic velocity and the resistive index of the testicular artery along the spermatic cord, the marginal portion of the testicular artery and the intratesticular branches of the testicular artery both in healthy adult and young bulls.Correlations between these parameters and characteristics of semen that was collected numerous times, before and after the Doppler ultrasound examination.Results: The peak systolic velocity and the end diastolic velocity measured in the testicular artery along the spermatic cord(supratesticular artery – SA) were variable among the bulls and within individual bulls, likely due to the convoluted course of the vessel. The resistive index was found highly repeatable in the same bull. A reduction in the resistive index was found between the supratesticular artery and the marginal portion of the testicular artery(P < 0.01), and between the marginal portion of the testicular artery and the intratesticular branches of the testicular artery(P < 0.05). No differences were recorded for the pulse wave Doppler ultrasound parameters in young bulls compared with adults. A significant correlation was found between the resistive index of the marginal portion of the testicular artery and total sperm in the ejaculate(r = 0.516, P < 0.05), the immature sperm(r = 0.462, P < 0.05), the teratoid sperm(r = 0.375, P < 0.05), and the "Dag defect" sperm(r = 0.389, P < 0.05). Similarly, the resistive index of the intratesticular branches of the testicular artery were found correlated with the total sperm number in the ejaculate(r = 0.568, P < 0.05), the immature sperm(r = 0.523, P < 0.05), the teratoid sperm(r = 0.418, P < 0.05), and the "Dag defect" sperm(r = 0.341, P < 0.05).Conclusions: The data presented in this study suggest that the resistive index, measured at the marginal portion of the testicular artery, could be an easy-to-perform parameter to evaluate the spermatogenesis quality in young bulls and normal adults.

Simulation and experiment of the cooling effect of trapped ion by pulsed laser

We investigate the process of pulsed laser cooling using a self-constructed molecular dynamics simulation(MDSimulation)program.We simulate the Doppler cooling process and pulsed laser Doppler cooling process of a single^(40)Ca^(+)ion,and the comparison with the experimental results shows that this self-constructed MD-Simulation program works well in the weak laser intensity situation.Furthermore,we analyze the pulsed laser Doppler cooling process of a single^(27)Al^(+)ion.This program can be used to analyze the molecular dynamic process of various situations of Doppler cooling in an ion trap,which could give predictions and experimental guidance.

All-fiber pulsed laser Doppler vibrometer development based on time-domain chopping techniques

A 1550 nm all-fiber pulsed laser Doppler vibrometer (LDV) based on time-domain chopping techniques is developed to overcome demodulation failures caused by multipath interference. The system adopts an adjustable configuration on pulse duration and pulse repetition frequency according to the distance. An experiment is carried out at a 25 m standoff with pulse duration of 80 ns, single pulse energy of 0.4 nJ, and pulse repetition frequency of 1 MHz. A waveform and spectrogram of the demodulated voice show that the pulsed LDV system has a good performance in long-range voice listening.

Clinical Evaluation of Color Doppler Ultrasound in Selecting the Optimal Treatment Modality for Infantile Hemangioma

Objective We investigated the efficacy and safety of 1064 nm Nd： YAG laser, intense pulsed light （IPL）, and lauromacrogol injection in the treatment of hemangioma, in order to evaluate the value of color Doppler ultrasound guidance in choosing the optimal treatment modality. Methods Infantile patients who were clinical diagnosed as hemangiomas were randomly divided into group A, who had color Doppler ultrasound examinations before the treatment, and group B who had the treatment without ultrasound evaluation. Patients in the group A were assigned into subgroups according to the depth of lesion by sonography： group A-1 for those who had a lesion depth 〈1.2 mm, and took intense pulsed light therapy; group A-2 for those who had a lesion depth ≥1.2mm and 〈 3 mm, and took long pulse 1064 nm Nd：YAG laser therapy; group A-3 for those who had a lesion depth ≥3mm and 〈5 mm, and were treated by IPL combined with long pulse 1064 nm Nd：YAG laser treatment; Group A-4 for those who had a lesion depth ≥5 mm, and took lauromacrogol injection therapy. Patients in the group B took long pulse 1064 nm Nd：YAG laser treatment without preoperative ultrasound evaluation. The efficacy and adverse reactions of the treatments between the groups were evaluated and compared statistically. Results Totally 113 patients with 128 skin lesions were enrolled in this study, 85 in the group A （mean age 6.8±7.9 months） and 28 in the group B （mean age 6.9±9.9 months）. The mean depth of hemangioma was 3.3±1.1 mm in the group A, ranging from 0.5-7.8 mm, with 0.8±0.4 mm, 2.2±0.4 mm, 4.2±0.6 mm and 6.2±0.7 mm in group A1, A2, A3 and A4, respectively. The cure rates and effective rates in the group A were significantly higher than those in the group B （cure rates： 64.5% vs 56.3%, U=3.378, P=0.045; effective rates： 89.5% vs 78.1%, U=4.163, P=0.041）. The adverse effect rates of the group A （vesicle 20.0%, pigmentation 46.9%, scarring 17.7%） were lower than those of the group B （vesicle 21.9%, pigmentation 60.4%, scarring 25.0%）. Incidences of pigmentation and scarring were statistically significantly different （U=3.884, P=0.034, and U=4.016, P=0.032 respectively） between the two groups. Conclusion With the guidance of color Doppler ultrasound, the efficacy and safety of long pulse 1064 nmNd：YAG laser, intense pulsed light, and lauromacrogol injection in the treatment of infantile hemangioma have better outcomes compared to laser treatment alone without preoperative ultrasound examination.

Human Body Surface Oscillations Remote Measurements by Means of Laser Doppler Interferometer

Experimental results of remote laser measurement of a time structure of a pulse waves are resulted. Occurrence of the pulse waves are connected with the rhythmic reduction of a myocardittm. Speed of pulse wave＇s propagation does not depend on speed of current of blood, it is defined by diameter of a vessel, by its walls thickness, by elasticity of a vessel, and also by rheological properties of blood. Measurement of parameters of pulse waves is important tbr definition of a condition of cardiovascular system. Ways of measurement of characteristics of pulse waves used now （acoustic, electric, optical） are contact. In some cases, for example, in clinics on treatment of burns and so forth, the question of remote measurement of processes hemodynamics by use of methods of laser sotmding is rather actual. The results described in work have shown outlook of development of laser methods of diagnostics for present purposes. The measurement technique used by authors is based on use of longitudinal Doppler effect which essence consists in change of frequency or length of a wave of radiation at reflection from moving surface. For smoothing the measured signal （clearing from noise） the program developed by authors on the basis of the wavelet-analysis was used. Experimental measurements are shown, that the laser method allows to register distinctly structure of pulse waves which is characterized by two peaks. The results of remote laser measurement of a time structure of a pulse waves confirm the assumption made on the basis of general-theoretical physical positions, that characteristics of pulse waves can be registered on the Doppler effect basis.

Difference analysis of Doppler ultrasound blood flow of Cunkou(radial artery)pulse,Renying(carotid artery)pulse,and Fuyang(anterior tibial artery)pulse

OBJECTIVE:To analyze the Doppler ultrasound blood flow of Renying(carotid artery)pulse,Cunkou(radial artery)pulse,and Fuyang(anterior tibial artery)pulse in the normal group and the functional constipation with gastrointestinal heat(FCGH)group,and to compare and explore the differences of Renying,Cunkou and Fuyang pulses.METHODS:Sixty normal subjects and 60 patients with gastrointestinal heat constipation were collected in the department of ultrasound,Beijing Anzhen Hospital,Capital Medical University.Doppler ultrasound was used to observe the blood flow indexes including maximum systolic velocity(Vp),maximum diastolic velocity(Vd),mean velocity(Vm),pulse index(PI),resistance index(RI),vascular diameter(D),and circulation blood flow cycle(ET)of Renying pulse,Cunkou pulse and Fuyang pulse in the normal group and patients with gastrointestinal heat constipation.The differences of these three pulses were compared between the normal group and the FCGH group.RESULTS:The PI,Vp,Vm,RI,and D of the three pulses in the normal group were statistically significant different(P<0.01).In the comparison of Doppler flow diagram of three pulses in the FCGH group,there were significant differences in PI,Vd,Vp,Vm,RI,and D(P<0.01).CONCLUSION:Under normal conditions,the indexes of Renying pulse Doppler flow diagram,Cunkou pulse Doppler flow diagram,and Fuyang pulse Doppler flow diagram are significantly different.In the FCGH group,most of the indexes of Renying pulse Doppler flow diagram,Cunkou pulse Doppler flow diagram,and Fuyang pulse Doppler flow diagram are different.This result verified the necessity of simultaneous examinations of all Renying,Cunkou,and Fuyang pulses in modern Chinese medicine.

HPRF pulse Doppler stepped frequency radar

Stepped frequency radar is a well known scheme to generate high range resolution profile （HRRP） of targets. Through appropriate radar parameter design, the radar enables both unambiguous velocity measurement and high resolution ranging within a single dwell in a high pulse repetition frequency （HPRF） mode. This paper analyzes in detail the design principle of the HPRF stepped frequency radar system, the solution to its ambiguity issue, as well as its signal processing method. Both theoretical analysis and simulation results demonstrate that the proposed radar scheme can work independently to solve the problem of motion compensation, and is therefore highly applicable to many new types of radar.

Pulse phase and doppler frequency estimation of X-ray pulsars under conditions of spacecraft and binary motion and its application in navigation

The pulse phase and doppler frequency estimation of X-ray pulsars in dynamic situations and its application in navigation is a problem that has not been fully investigated. In this paper, solutions are proposed to solve this problem under conditions of spacecraft and binary motion. A high-precision doppler frequency (velocity) measurement model as well as a phase (range) measurement model is established. The averaged maximum-likelihood estimator is developed for the dynamic pulse phase estimation. The pulse phase tracking technique is used in the doppler frequency determination. The tracking filter is redesigned and compared with the existing algorithms. The comparison verifies the advantage of the filter algorithm presented in this pa- per. Unlike traditional views, it is found that in dynamic situations, shorter observation interval lengths will result in higher-accuracy phase and frequency estimates as the tracking filter outputs. A photon-level integrated numerical simulation is performed. Simulation results testify to the validity of the proposed phase and doppler frequency estimation scheme, and show that incorporation of velocity measurements as well as the range ones into the navigation estimator will improve the navigation steady-state performance.

X-ray pulsar-based navigation using pulse phase and Doppler frequency measurements

In order to eliminate the impact of the Doppler effects caused by the motion of the spacecraft on the X-ray pulsar-based navigation, an innovative navigation method using the pulse phase and Doppler frequency measurements of the X-ray pulsars is proposed. Given the initial estimate of the spacecraft's state,the real-time photon arrival model is established at the spacecraft with respect to the spacecraft's position and velocity predicted by the orbit dynamic model and their estimation errors. On this basis, a maximum likelihood estimation algorithm directly using the observed photon event timestamps is developed to extract a single pair of pulse phase and Doppler frequency measurements caused by the spacecraft's state estimation error. Since the phase estimation error increases as the observation time increases, we propose a new measurement updating scheme of referring the measurements to the middle time of an observation interval. By using the ground-based simulation system of X-ray pulsar signals, a series of photon-level simulations are performed. The results testify to the feasibility and real-timeliness of the proposed navigation method, and show that the incorporation of the Doppler measurement as well as the pulse phase into the navigation filter can improve the navigation accuracy.

Doppler shift of a laser pulse beam scattered by a rotating cone and cylinder

Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the detected area elements are analyzed by geometric methods. The Doppler shift characteristics of the rotating cone and cylinder are discussed and the difference between the laser pulse beam and the plane wave scattered from the same rotating target is compared accordingly. Numerical simulations show that the Doppler shift is tightly relevant to their dimensions, speeds, and so on. In the same incidence conditions, the pulse beam and plane wave have difference peak values and the same Doppler shift bandwidth. If the waist radius of the pulse beam is larger, the peak value is higher, and the Doppler shifts are proportional to the speed of the rotating target. By virtue of our theoretical model, we probe into the scattered characteristics of the Doppler shifts of a laser pulse beam, which would benefit target identification in national defense.

基于遗传算法的机载中重频高效多维优化

机载脉冲多普勒(PD)雷达的重频组设计是雷达总体设计的基础,直接影响雷达的性能和应用场景。在中重频组设计过程中,必须考虑多维度参数的优化,由于可调整参数多,会导致潜在组合数膨胀严重,对计算资源和时间提出了极大的挑战。传统的优化方法,即便在限定参数范围后,仍面临穷举组合数庞大的问题。此外,机载雷达系统设计周期通常较短,模式需求多变,需要在较短时间内完成方案前期参数的选择和初步优化,便于开展后续设计。本文提出了一种基于遗传算法的高效多维优化方法,不仅增加了优化维度以更好满足工程需求,同时显著提升了优化效率。通过应用实例验证了所提方法的有效性,对机载PD雷达总体设计论证具有重要价值。

基于多频脉冲采样的血流速度估计方法

传统双模超声技术相较于新兴技术更具实现可穿戴化的潜力。在进行脉冲多普勒血流速度估计时,双模超声需同时发射B模式脉冲进行成像定位,这要求B模式脉冲和多普勒脉冲共享采样时间。采用基于单频多普勒脉冲的稀疏间隔发射方式可以解决这一问题,但常见的稀疏发射排布方式(如嵌套发射、互质发射等)存在采样时间窗较长的缺点,特别是在血流速度变化明显的情况下存在时间分辨率不足的问题。此外,长时间窗包含了较多的血流速度分量,容易由于稀疏采样引起伪影,从而影响血流速度估计的准确性。因此,文中提出了一种基于多频脉冲采样的新型血流速度估计方法。首先,构建了多频脉冲采样的回波模型,并对该模型进行推导,证明了在频率衰减平稳假设下,该数学模型等价于单频多普勒脉冲稀疏发射方式,即多频脉冲采样可以通过较短的时间窗实现类似于基于单频脉冲采样模式的长时间窗的性能,从而提高血流速度谱的时间分辨率和估计精度;然后,提出了两种可用于多频脉冲采样模式的血流速度谱的构建方法,分别为复杂度较低的BMUSIC算法和伪影抑制效果较佳的VMUSIC算法。基于FieldⅡ仿真数据和人体实测数据的实验结果表明:相较于单频多普勒脉冲稀疏发射方式,文中方法不仅可以采用较短的时间窗提升血流速度谱的时间分辨率,还可以获得连续、清晰、精度较高且伪影抑制效果较佳的血流速度估计结果;在人体实测数据实验中,由于实验条件所限,文中方法无法实现非整数倍频,未能充分展现VMUSIC算法的性能优势。