Cepstrum

About: Cepstrum is a research topic. Over the lifetime, 3346 publications have been published within this topic receiving 55742 citations.

Mean‐scatterer spacing estimates with spectral correlation

Abstract: An ultrasonic backscattered signal from material comprised of quasiperiodic scatterers exhibit redundancy over both its phase and magnitude spectra. This paper addresses the problem of estimating mean‐scatterer spacing from the backscattered ultrasound signal using spectral redundancy characterized by the spectral autocorrelation (SAC) function. Mean‐scatterer spacing estimates are compared for techniques that use the cepstrum and the SAC function. A‐scan models consist of a collection of regular scatterers with Gamma distributed spacings embedded in diffuse scatterers with uniform distributed spacings. The model accounts for attenuation by convolving the frequency dependent scattering centers with a time‐varying system response. Simulation results indicate that SAC‐based estimates converge more reliably over smaller amounts of data than cepstrum‐based estimates. A major reason for the performance advantage is the use of phase information by the SAC function, while the cepstrum uses a phaseless power spec...

A practical handbook of speech coders

Abstract: INTRODUCTION SPEECH PRODUCTION The Speech Chain Articulation Source-Filter Model SPEECH ANALYSIS TECHNIQUES Sampling and the Speech Waveform Systems and Filtering z Transform Fourier Transform Discrete Fourier Transform Windowing Signal Segments LINEAR PREDICTION VOCAL TRACT MODELING Sound Propagation in the Vocal Tract Estimation of LP Parameters Transformations of LP Parameters for Quantization Examples of LP Modeling PITCH EXTRACTION Autocorrelation Pitch Extraction Cepstral Pitch Extraction Frequency-Domain Error Minimization Pitch Tracking AUDITORY INFORMATION PROCESSING The Basilar Membrane: A Spectrum Analyzer Critical Bands Thresholds of Audibility and Detectability Monaural Masking QUANTIZATION AND WAVEFORM CODERS Uniform Quantization Nonlinear Quantization Adaptive Quantization Vector Quantization QUALITY EVALUATION Objective Measures Subjective Measures Perceptual Objective Measures VOICE CODING CONCEPTS Channel Vocoder Formant Vocoders The Sinusoidal Speech Coder Linear Prediction Vocoder LINEAR PREDICTION ANALYSIS BY SYNTHESIS Analysis by Synthesis Estimation of Excitation Multi-Pulse Linear Prediction Coder Regular Pulse Excited LP Coder Code Excited Linear Prediction Coder MIXED EXCITATION CODING Multi-Band Excitation Vocoder Mixed Excitation Linear Prediction Coder Split Band LPC Coder Harmonic Vector Excitation Coder Waveform Interpolation Coding PERCEPTUAL SPEECH CODING Auditory Processing of Speech Perceptual Coding Considerations Research in Perceptual Speech Coding APPENDIX: RELATED INTERNET SITES

Method of determining drill bit wear

Abstract: A method is provided for determining the state of wear of a multicone drill bit. Vibrations generated by the working drill bit are detected and converted into a time oscillatory signal from which a frequency spectrum is derived. The periodicity of the frequency spectrum is extracted. The rate of rotation of at least one cone is determined from the periodicity and the state of wear of the drill bit is derived from the rate of cone rotation. The oscillatory signal represents the variation in amplitude of the vertical or torsional force applied to the drill bit. To extract periodicity, a set of harmonics in the frequency spectrum is given prominence by computing the cepstrum of the frequency spectrum or by obtaining an harmonic-enhanced spectrum. The fundamental frequency in the set of harmonics is determined and the rate of cone rotation is derived from the fundamental frequency.