lsp2sp#

class diffsptk.LineSpectralPairsToSpectrum(lsp_order, fft_length, alpha=0, gamma=-1, log_gain=False, out_format='power')[source]#

See this page for details.

Parameters:

lsp_orderint >= 0 [scalar]: Order of line spectral pairs, \(M\).
fft_lengthint >= 1 [scalar]: Number of FFT bins, \(L\).
alphafloat [-1 < alpha < 1]: Warping factor, \(\alpha\).
gammafloat [-1 <= gamma < 0]: Gamma, \(\gamma\).
log_gainbool [scalar]: If True, assume input gain is in log scale.
out_format[‘db’, ‘log-magnitude’, ‘magnitude’, ‘power’]: Output format.

forward(w)[source]#

Convert line spectral pairs to spectrum.

Parameters:

wTensor [shape=(…, M+1)]: Line spectral pairs in radians.

Returns:

spTensor [shape=(…, L/2+1)]: Amplitude spectrum.

Examples

>>> x = diffsptk.nrand(4)
>>> x
tensor([ 2.1110, -1.4767,  1.2490,  2.4201,  1.5429])
>>> lpc = diffsptk.LPC(3, 5)
>>> a = lpc(x)
>>> lpc2lsp = diffsptk.LinearPredictiveCoefficientsToLineSpectralPairs(3)
>>> w = lpc2lsp(a)
>>> lsp2sp = diffsptk.LineSpectralPairsToSpectrum(3, 8)
>>> sp = lsp2sp(w)
>>> sp
tensor([31.3541, 13.7932, 14.7454, 16.9510, 10.4759])