共查询到20条相似文献,搜索用时 31 毫秒
1.
The interaction between the input filter and the control loop of switching regulators often results in detrimental effects, such as loop instability, degradation of transient response, and audiosusceptibility, etc. The concept of pole-zero cancellation is employed to mitigate some of these detrimental effects and is implemented using a novel feedforward loop, in addition to existing feedback loops of a buck regulator. Experimental results are presented which show excellent correlation with theory. 相似文献
2.
Berner J.B. Layland M.J. Kinman P.W. 《IEEE transactions on aerospace and electronic systems》2001,37(3):957-964
A flexible loop filter design for spacecraft phase-locked receivers is proposed. The loop filter is implemented as digital hardware with coefficients that are set by registers. Either a perfect or an imperfect integrating loop filter can be effected. This flexibility is important since not one type of loop filter is preferred for all circumstances. An imperfect integrator is preferred when, as is often the case for spacecraft receivers, it is important to minimize the best-lock frequency drift of an idling loop. A perfect integrator is preferred when the tracking performance of the loop is the most important consideration 相似文献
3.
给出了一种异步时钟恢复的最佳平方逼近插值滤波器设计,该滤波器基于最小平方逼近理论,采用易于硬件实现的Farrow结构;克服了拉格朗日插值滤波器参数固定而窗函数截短插值滤波器结构复杂的问题。对我国航天测控设备的数字化和小型化具有较好的应用价值。 相似文献
4.
An exact mathematical model is developed for a discrete loop of a general order particularly suitable for digital computation. The deterministic response of the loop to the phase step and the frequency step is investigated. The design of the digital filter for the second-order loop is considered. Use is made of the incremental phase plane to study the phase error behavior of the loop. The model of the noisy loop is derived and the optimization of the loop filter for minimum mean-square error is considered. 相似文献
5.
A perfect third-order loop filter design that can be implemented as a digital filter is obtained which minimizes the noiseless steady-state acceleration rate (jerk) error for a fixed loop noise bandwidth. Simulations were performed to obtain transient responses of the third-order loop plus a sample fourth-order loop under a jerk input. The results enable one to obtain a loop design that minimizes the loop noise bandwidth required for a given steady-state jerk error and thus obtain better noise jitter performance. 相似文献
6.
Gupta Someshwar C. Bayless Jon W. Hummels Donald R. 《IEEE transactions on aerospace and electronic systems》1968,(6):855-863
This paper is primarily an investigaton of a second-order phased-locked loop in the threshold region, with the loop filter chosen as (1/1+?s) or (1+?1s/1+?s). First-order loop results are also given. Effects of loop parameters, detuning error, and modulation are studied. It is shown that the loop with filter (1+?1s/1+?s) can be built two ways with same bandwidth and damping. One loop gives much better threshold than the other. The analytical results are supported by computer simulation as well as experimental work obtained by hardware simulation of the loop. 相似文献
7.
李海玲 《西安航空技术高等专科学校学报》2008,26(3):58-60
介绍了一种通过在微带开环谐振滤波器中引入交叉耦合,产生一对传输极点,从而提高通带选择性的滤波器设计方法。讨论了这种滤波器的综合方法和实现流程。实际设计了一个六阶开环谐振滤波器,并给出了全波仿真结果。分析和仿真都表明这种滤波器具有体积紧凑、选择性高的优点。 相似文献
8.
分析了零点配置/回路传函恢复(ZP/LTR)方法稳定性, 给出并证明了其稳定性条件.但该条件较为苛刻, 限制了ZP/LTR方法的应用.为了对ZP/LTR方法改进, 在设计过程中引入了Kal man滤波器, 通过选取特殊的参数, 使Kal man滤波器回路逼近并取代原目标回路, 从而在保留ZP/LTR方法性能的同时, 通过保证Kal man滤波器回路的稳定性保证了最后闭环系统的稳定性.给出并证明了改进后的ZP/LTR方法的稳定性条件, 指出改进后的ZP/LTR方法的稳定性条件较为宽松, 拓宽了原ZP/LTR方法的应用范围. 相似文献
9.
The interaction between the input filter and the regulator often causes serious degradation of performance. The reduction in loop gain due to input filter interaction can result in system instability. An exact stability analysis of the buck regulator system is presented. The input filter parameter values are varied and system instability is predicted for the case without feedforward. The eigenvalues of the system can be brought back into the unit circle and the system thus stabilized with the addition of the feedforward loop. Measurements made for the cases with and without feedforward confirm the analytical prediction. 相似文献
10.
基于UKF准开环结构的高动态载波跟踪环路 总被引:2,自引:1,他引:1
对高动态环境下的全球卫星导航系统(GNSS)载波信号跟踪方法进行了研究。在分析高动态载波信号模型的基础上,提出了一种基于无迹卡尔曼滤波(UKF)的准开环载波跟踪方法。此方法能够消除导航数据二进制相移键控(BPSK)调制的影响,并采用四维UKF相位估计模型提高跟踪精度,同时对估计值进行补偿以减少滤波器的滞后性。通过模拟接收机的高动态运动轨迹,从跟踪误差、跟踪结果和补偿效果3个方面,与基于卡尔曼滤波(KF)的锁频环(FLL)辅助锁相环(PLL)结构的传统跟踪方法进行比较,结果表明基于UKF的准开环跟踪方法能够有效地完成高动态环境下的载波跟踪。 相似文献
11.
12.
13.
14.
传统的北斗接收机一般采用标量跟踪环,每个通道的卫星相互独立,在此
基础上,又发展起来了基于矢量跟踪的接收机,使每个通道的卫星跟踪不再相互独立。
提出的基于I、Q 信号观测的接收机跟踪环路,保留矢量跟踪的特点,并且采用EKF 作
为跟踪环路预处理滤波器,代替传统跟踪环路的鉴别器,可以在高动态的环境下对卫星
信号进行跟踪,提高环路的稳定性,从而可以有效地提高BDS/INS 深组合导航滤波器观
测量的估计精度。主要对高动态信号跟踪进行仿真,并与传统的标量跟踪方法和矢量跟
踪方法的跟踪能力进行比较。实验表明, 改进的矢量跟踪环能够在高动态的环境下运
行,比起传统环路有更小的跟踪误差。 相似文献
15.
The LMS adaptive array requires an integrator in each weight feedback control loop. In practice the integrator is often replaced by a low-pass filter, i.e., by a filter with a single pole at s = - ? (where s is complex frequency). The effect of this pole position on array performance is examined. It is shown that to obtain optimal performance from the array, ? must be less than k?2, where k is the loop gain and ?2 is the thermal noise power per element. When at exceeds k?2, the output signal-to-inter ference-plus-noise ratio from the array is degraded for intermediate values of interference power. 相似文献
16.
17.
Phase-locked high-frequency multipliers which do not have powergreedy frequency dividers in the feedback loop, but which do have a sample-and-hold circuit as a phase detector are hard to design, due to conflicting requirements which determine the choice for loop gain and loop bandwidth. A circuit is described that acts as a frequency control if the loop is not locked and as a phase control once the loop can be locked. The loop filter has to be optimized for the locked condition only, and the allowable preset error is more than 80 percent of the sample frequency. The circuit also indicates whether the oscillator frequency is an odd or an even multiple of the sample frequency. Pull-in is at least an order of magnitude faster than with phase control alone. 相似文献
18.
Phase-locked-loop (PLL) bit synchronizers often employ integrate-and-dump type phase detectors that provide phase error information only at discrete points in time. Usually these phase detectors are followed by sample-and-hold circuits to produce a stairstep error voltage as the input to a standard analog circuit loop filter. When the loop is configured in this manner, it is referred to as a hybrid PLL. Sampled-data analysis methods (Z transforms) are used to determine the stability and transient response of this loop. 相似文献
19.
Although there is a well-defined relation between range and range rate, in conventional pulse-Doppler tracking radars the range-gate and frequency control loops are usually closed independently. In this paper, the optimum cross- coupled stationary tracking filter is derived, in which the range error signal is used to boost the frequency loop, and vice versa. The filter is derived for a general case of target dynamics and uncorrelated white noise in both the range gate and frequency control channels. It is shown that its tracking performance is superior to that of the conventional uncoupled tracking loop for reliable frequency channel operation. In solving the usually difficult degenerated Riccati matrix equation, a simple solution is obtained by applying the method of completion of the square to matrixes. 相似文献