windowfilter(1) [debian man page]
WINDOWFILTER(1) General Commands Manual WINDOWFILTER(1) NAME
windowfilter - design an FIR digital filter by the window method DESCRIPTION
The windowfilter program designs an FIR digital filter for use with the resample program. Just run the program and type ? at its prompts to get an explanation of its options. REFERENCES
Digital Signal Processing Committee, ed., Programs for Digital Signal Processing, IEEE Press, New York, 1979. J. F. Kaiser, "Using the I0-sinh Window Function," Proc. IEEE Int. Symp. on Circuits and Syst., April 22-25, pp. 20-23, 1974. F. J. Harris, "On the Use of Windows for Harmonic Analysis with the Discrete Fourier Transform," Proceedings of the IEEE, vol. 66, no. 1, pp. 51-83. Jan. 1978. A. H. Nuttall, "Some Windows with Very Good Sidelobe Behavior," IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. ASSP-29, no. 1, pp. 84-91, Feb. 1981. L. R. Rabiner and B. Gold, Theory and Application of Digital Signal Processing, Prentice-Hall Inc., Englewood Cliffs, NJ, 1975. CCRMA
19 Jun 2002 WINDOWFILTER(1)
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mlib_SignalCepstral_S16(3MLIB) mediaLib Library Functions mlib_SignalCepstral_S16(3MLIB) NAME
mlib_SignalCepstral_S16 - perform cepstral analysis SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ] #include <mlib.h> mlib_status mlib_SignalCepstral_S16(mlib_s16 *cepst, mlib_s32 cscale, const mlib_s16 *signal, void *state); DESCRIPTION
The mlib_SignalCepstral_S16() function performs cepstral analysis. The user supplied scaling factor will be used and the output will be saturated if necessary. The basic operations to compute the cepstrum is shown below. +-----------+ +--------+ +-----------+ | Fourier | | | | Inverse | ----->| |----->| log|*| |------>| Fourier |-----> x(n) | Transform | X(k) | | X'(k) | Transform | c(n) +-----------+ +--------+ +-----------+ where x(n) is the input signal and c(n) is its cepstrum. In mathematics, they are N-1 2*PI*k*n X(k) = SUM x(n) * exp(-j*----------) n=0 N X'(k) = log|X(k)| 1 N-1 2*PI*k*n c(n) = --- SUM X'(k) * exp(j*----------) N n=0 N Since X'(k) is real and even (symmetric), i.e. X'(k) = X'(N - k) the c(n) is real and the equation becomes Cosine transform. 1 N-1 2*PI*k*n c(n) = --- SUM X'(k) * cos(----------) N n=0 N The cepstral coefficients in LPC is a special case of the above. See Digital Signal Processing by Alan V. Oppenheim and Ronald W. Schafer, Prentice Hall, 1974. See Fundamentals of Speech Recognition by Lawrence Rabinerand Biing-Hwang Juang, Prentice Hall, 1993. PARAMETERS
The function takes the following arguments: cepst The cepstral coefficients. cscale The scaling factor of cepstral coefficients, where actual_data = output_data * 2**(-scaling_factor). signal The input signal vector, the signal samples are in Q15 format. state Pointer to the internal state structure. RETURN VALUES
The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Evolving | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
mlib_SignalCepstralInit_S16(3MLIB), mlib_SignalCepstral_S16_Adp(3MLIB), mlib_SignalCepstralFree_S16(3MLIB), attributes(5) SunOS 5.10 10 Nov 2004 mlib_SignalCepstral_S16(3MLIB)