Damped sinusoidal signals parameter estimation in frequency domain

Parameter estimation of noisy damped sinusoidal signals in the frequency domain is presented in this paper. The advantage of the frequency domain approach is having the spectral energy concentrated in frequency domain samples. However, the least squares criterion for frequency estimation using frequency domain samples is nonlinear. A low complexity three-sample estimation algorithm (TSEA) for solving the nonlinear problem is proposed. Using the TSEA for initialization, a frequency domain nonlinear least squares (FD-NLS) estimation algorithm is then proposed. In the case of white Gaussian noise, it yields maximum likelihood estimates, verified by simulation results. A time domain NLS (TD-NLS) estimation algorithm is also proposed for comparison.The Cramer-Rao lower bound (CRLB) of the frequency domain estimation algorithms is derived. The theoretical analysis shows that the FD-NLS can yield a near-optimal performance with few energy-concentrated samples. On the other hand, the TD-NLS does not have the energy concentration property and requires more time domain samples to perform satisfactory estimation. Simulation results verify that the frequency domain estimation algorithms provide better tradeoff between computational complexity and estimation accuracy than time domain algorithms.     

Peak-amplitude detector for sinusoidal signals

A circuit technique is proposed for detecting the peak amplitude of a sinusoidal signal using Pythagoras's law without requiring a simultaneous equal-amplitude quadrature signal. The number of four-quadrant multipliers required is only two.     

改进的DFT正弦信号频率估计

通过分析Candan算法和2N点DFT算法的性能,本文提出了一种改进的基于DFT的正弦信号频率估计算法。在对原始信号进行必要的离散化预处理后,在粗估计阶段利用Candan算法估计出频率偏差后,利用该频偏对原始信号进行频率修正。然后对修正后的原始信号进行2N点DFT算法精估计。由于增加了原始信号的频率修正步骤,该算法发挥了Candan算法和2N点DFT算法的优点,同时避免了其缺点。仿真结果表明,在相对频偏为任意值时,改进算法频率估计的均方根误差均接近克拉美罗下限,并且估计性能优于现有的频率估计算法。      

Damped transient power clamps for improved ESD protection of CMOS

Small transient power clamps that include inverters may oscillate and disengage during an HBM ESD event. A transient power clamp created in a 0.25 μm process revealed an interesting solution to the problem. Adding a resistance to the final inverter may improve ESD performance.     

Predictive digital filtering of sinusoidal signals

The p-step ahead predictive filters for narrowband waveforms with m distinct spectral peaks are considered. By minimization of the noise gain, the coefficients of the optimal Lth order FIR predictor is derived, where L>2m-1. The minimum-length FIR predictor is given by L=2m-1, and the feedback extension of this predictor is studied. Design of feedback gains subject to different optimization criteria is studied in detail. The generalization to complex-valued signals, cascaded predictors, and adaptive predictors are also included. Several design and simulation examples are presented     

An instantaneous peak detection method for three-phase sinusoidal signals

This paper presents a new amplitude detection method for three-phase sinusoidal signals. The proposed detection method is based on calculation of the Park transformation. This method measures the amplitude of three-phase signals instantaneously and the ideal and non-ideal conditions are analysed. An electronic circuit for implementing this method is developed and tested to demonstrate the performance of the proposed method.     

基于频率模型和时频分析的正弦信号频率高精度估计算法

利用时频分析方法估计信号瞬时频率,在低信噪比条件下估计性能较差,但在时频图中,信号频率的变化趋势具有一定的规律,基本上都是围绕着信号的真实频率。基于此,给出了一种结合时频分析和信号频率模型相结合的方法,以实现信号瞬时频率的高精度估计。利用时频分析具有的良好时频分布的特点,采用最大能量方法（ME）预先估计得到信号的预估计瞬时频率（EIF）;再利用瞬时频率连续性、平滑性的先验信息,建立了信号瞬时频率估计模型,并采用概率最大原理(MP)估计瞬时频率概率最大的统计变化,估计得到预估计瞬时频率的滤波起始点;最后利用卡尔曼滤波和平滑算法对预估计瞬时频率进行滤波和平滑,从而得到信号频率的精确估计。      

Oversampled Gabor representation for transient signals

Considers the Gabor representation that uses a one-sided exponential window for detection and analysis of transient signals. Earlier results on the critically sampled case are extended to the more practically useful oversampled case. For oversampling by an integer factor, the authors derive an explicit analytical expression for the dual window (dual frame) function required for computing the Gabor representation. Based on this expression they develop an efficient procedure for computing the Gabor coefficients. Finally, they demonstrate the performance of the method by numerical examples     

All-purpose and plug-in power-law detectors for transient signals

A power-law statistic operating on discrete Fourier transform (DFT) data has emerged as a basis for a remarkably robust detector of transient signals having unknown structure, location, and strength. We offer a number of improvements to Nuttall's (1994) original power-law detector. Specifically, the power-law detector requires that its data be prenormalized and spectrally white; a constant false-alarm rate (CFAR) and self-whitening version is developed and analyzed. Further, it is noted that transient signals tend to be contiguous both in the temporal and frequency sense, and consequently, new power-law detectors in the frequency and the wavelet domains are given. The resulting detectors offer exceptional performance and are extremely easy to implement. There are no parameters to tune. They may be considered “plug-in” solutions to the transient detection problem and are “all-purpose” in that they make minimal assumptions on the structure of the transient signal, save of some degree of agglomeration of energy in time and/or frequency     

A new peak detection method for the three-phase sinusoidal signals

An instantaneous amplitude detection method for the three-phase sinusoidal signals is proposed. The proposed method can measure the amplitude of the three-phase signals without any delay by using only two of the three-phase signals. The performance of this method under the ideal and nonideal conditions is analyzed. To demonstrate the performance of the proposed method, an electronic circuit for implementing this method is developed and tested     

用于正弦波频率估计的修正Kay算法

Kay算法能够估计出采样点较少的正弦波频率,但低信噪比下估计性能不佳.针对此问题,提出了修正Kay算法.首先基于最大似然估计准则,推导了观测信号模值与相位的条件概率密度函数,进而重建了Kay算法的相位差噪声矢量协方差矩阵与权值矩阵.实验结果表明,修正算法能够有效估计正弦波信号频率,与Kay算法相比,抗噪性更强.     

Analytical formula for three points sinusoidal signals amplitude estimation errors

In this note, we show that the amplitude estimation of sinusoidal signals proposed in Wu and Hong [Wu, S.T., and Hong, J.L. (2010), ‘Five-point Amplitude Estimation of Sinusoidal Signals: With Application to LVDT Signal Conditioning’, IEEE Transactions on Instrumentation and Measurement, 59, 623–630] is a particular case of Vizireanu and Halunga [Vizireanu, D.N, and Halunga, S.V. (2011), ‘Single Sine Wave Parameters Estimation Method Based on Four Equally Spaced Samples’, International Journal of Electronics, 98(7), pp. 941–948]. An analytical formula for amplitude estimation errors as effects of sampling period deviation is obtained.     

A method for fast amplitude detection of variable period sinusoidal signals

In this work a method for fast detection of sinusoidal signal amplitude of variable period is proposed. Information for the signal amplitude is taken with several sample pulses in each half period with the aid of a multiplier and a differentiator. The sampled signal values are held and equalized with the signal amplitude by a weighting amplifier.     

基于低速采样的多正弦波信号频率估计

高频段信号由于受到A/D转换器和后续信号处理器件运算速度和成本的限制,其处理往往难以实现,为解决此问题,提出了一种新的基于低速采样的高频段多正弦波信号频率估计方法。首先将含有多个频率互异的多正弦波信号经过功分器分成两路信号,然后分别用不同的采样率对这两路信号进行低速采样,用傅立叶变换及基于改进的Rife算法与Quinn算法来估计两路信号低速采样后的频率,接下来利用中国余数定理对多个信号的频谱快速配对解模糊准确的估计出各个信号的频率。该方法在工程上易于实现,可同时实现低的采样速率与高精度估计,而且在较低信噪比的情况下仍可获得较高的估计精度。给出了该方法的具体步骤,通过计算机仿真试验验证了该方法的有效性。      

A parameter estimation scheme for damped sinusoidal signals basedon low-rank Hankel approximation

Most of the existing algorithms for parameter estimation of damped sinusoidal signals are based only on the low-rank approximation of the prediction matrix and ignore the Hankel property of the prediction matrix. We propose a modified Kumaresan-Tufts (MKT) algorithm exploiting both rank-deficient and Hankel properties of the prediction matrix. Computer simulation results demonstrate that compared with the original Kumaresan-Tufts (1982) algorithm and the matrix pencil algorithm, the MKT algorithm has a lower noise threshold and can estimate the parameters of signal with larger damping factors     

A simple method for estimating the spectrum of exponentially damped sinusoidal signals

An algorithm is presented for the spectrum of experimentally obtained exponentially damped sinusoidal signals. The implementation of this algorithm is straightforward and requires only simple basic mathematical operations. Applications of the algorithm are illustrated by several examples.     

A new microcontroller-based technique for generating variable voltage/frequency sinusoidal PWM signals

This paper presents a flexible and robust microcontroller-based technique for generating the control signals of any sinusoidal pulse width modulation (SPWM) scheme for variable voltage/frequency output. The proposed technique exploits the fully static design of a high-speed microcontroller and generates the PWM control signals by varying the controller's clock, while keeping the number of the algorithm processing states constant. As the experimental results show, the technique can be used for transient-free frequency and/or voltage changes with very good resolution and a wide range of applications.     

Adaptive frequency estimation of sinusoidal signals in colored non-Gaussian noises

This paper studies the problem of sinusoidal frequency estimation in colored non-Gaussian ARMA noises. A new adaptive approach is proposed by using the second-and third-order statistics of the measurements. Because of the simultaneous establishment of the signal and noise models, the new approach is applicable for tracking the frequencies at each time instant for stationary and nonstationary signal and/or noise cases. The effectiveness of the new approach is demonstrated by extensive computer simulations. As expected, the approach proposed in this paper outperforms the correlation-based approaches in suppressing the effects of the colored non-Gaussian ARMA noises.     

Continuous phase shift of sinusoidal signals using injection locked oscillators

This work presents an alternative to generate continuous phase shift of sinusoidal signals based on the use of super harmonic injection locked oscillators (ILO). The proposed circuit is a second harmonic ILO with varactor diodes as tuning elements. In the locking state, by changing the varactor bias, a phase shift instead of a frequency shift is observed at the oscillator output. By combining two of these circuits, relative phases up to /spl plusmn/90/spl deg/ could be achieved. Two prototypes of the circuit have been implemented and tested, a hybrid version working in the range of 200-300 MHz and a multichip module (MCM) version covering the 900-1000 MHz band.