Frequency Resolution

We develop a canonical, adaptive cascade-structure IIR notch filter to detect and track multiple time-varying frequencies in additive white Gaussian noise. The algorithm uses allpass frequency transformation filters and a truncated gradient. Simulations indicate that our algorithm is computationally simple, converges rapidly, and has good frequency resolution

We present an algorithm for the online detection of rotor bar breakage in induction motors through the use of wavelet packet decomposition (WPD) and neural networks. The system provides a feature representation of multiple frequency resolutions for faulty modes and accurately differentiates between healthy and faulty conditions, and its main applicability is to dynamic time-variant signals experienced in induction motors

This paper presents a Fractional-N frequency synthesizer for WiMAX applications. Fractional-N phase-locked loop (PLL) architecture is selected for higher reference frequency, smaller division ratio, better frequency resolution, and the possibility of agile switching between the channels. Fractional-N synthesizer also alleviates PLL design constraints for phase noise and reference spur. Employing accumulator and linear feedback shift registers (LFSR) are the common techniques to provide the fractional division ratio. The generation of the fractional spurs is the main shortcoming due to utilizing these kinds of dithering circuits. A sigma-delta fractional-N frequency synthesizer (FS) improves the phase noise performance using a spur reduction method. Several kinds of sigma-delta structures are designed and verified via MATLAB/SIMULINK. Also the core of the synthesizer apart from the dithering circuits is simulated using ADS2009 in 0.13umCMOS technology. The simulation results illustra...

We discuss the use of cochlear models for spectrum analysis at radio frequencies. We describe performance characteristics of such models, including noise, dynamic range, and frequency resolution. We show that the addition of phase information improves frequency estimation as compared to the use of amplitude information alone. In particular, the use of both amplitude and phase information in a novel nonlinear bio-inspired center-surround coincidence-detection stage simultaneously improves frequency estimation and implements a lowpass-to-bandpass transformation on cochlear outputs. In order to further improve frequency estimation we propose a novel wireless receiver architecture that is a broadband generalization of narrowband heterodyning systems commonly used in radio. We term this architecture cochlear heterodyning. It exploits the efficiency of cochlear spectrum analysis to perform parallel, multi-scale analysis of wideband signals and can be constructed with cochlea-like traveling-wave structures. When combined with our prior work on an RF cochlea, such architectures may be useful in cognitive radios for creating RF foveas that select narrowband components present within wideband, but spectrally sparse signals. The operation of RF foveas is analogous to how the eye foveates on narrow but interesting portions of an image. Analogies between spectrum analysis and the process of successive-subranging analog-to-digital conversion illustrate how successively finer frequency resolution is achieved in an RF fovea. Finally, we show that RF foveas can be used in feedback loops to perform interference cancellation.

ABSTRACT In this work the concept, circuits and algorithms for an efficient off-line Built-In Self-Test (BIST) in watt hour meters are presented. On-chip signal generator is needed and additional digital hardware is necessary to evaluate the result. For a good signal to noise ratio (SNR) as well as good frequency resolution, a large number of samples would be needed to accurately calculate the FFT of the result. This approach is time-consuming and inappropriate for BIST, since it requires too much silicon area. We tried to avoid FFT calculation and replace it with small digital hardware and hardware algorithm running on the chip. The most important errors, which may happen in measurement path during the operation of the watt hour meter, can be efficiently detected. The parameters obtained by the suggested BIST hardware/algorithm were compared to the results obtained by the FFT for verification. The results confirm that the proposed concept of BIST could be used for an efficient on chip and off-line built-in self-test.

In this paper, we investigated the memorization variation during the observation of TV commercials by tracking the cortical activity. According to the priori knowledge, in the human scalp EEG, the theta band responds selectively to the encoding of new information into episodic memory. There will be a significantly larger increase in theta power during the memory encoding. Then we proposed a novel method to calculate the memorization index during the observation, which is an important index to evaluate the effectiveness of the TV commercial. We used the Power Spectral Density (PSD) to calculate the power in frequency domain and assign each electrode with different weight. And in time domain, the weighted Global Field Power (w-GFP) was used to be the memorization index. So this method has high time resolution and frequency resolution. The results of w-GFP suggest that this kind of technology is able to track variation of the cerebral activity related to cognitive tasks such as reflecting memorization level during observation TV commercials. This method also suggests the possibility to identify frame segments of particular attractive for marketers which is important to improve the effectiveness of TV commercial.

In this paper, we present results for a combined wavelet warped linear prediction (WLP) audio coder. In contrast to conventional LP, WLP allows for the control of frequency resolution to closely match the response of the human auditory system. The coder first uses WLP analysis on each frame of audio, and then applies a discrete wavelet transform (DWT) to the residual signal (prediction error). A psychoacoustic model is used in parallel to obtain a global masking threshold used in bit allocation. Bits are dynamically allocated to the DWT coefficients in an attempt to minimise the perceptually significant quantisation error. For monophonic signals sampled at 44.1 kHz, the coder achieves near transparent quality for a variety of speech and music signals at an average bit-rate of 64 kb/s. The power of the proposed coder resides in its easy scalability to lower bit rates