High frequency content recovering method and device for over-sampled synthesized wideband signal

DC
  • US 7,151,802 B1
  • Filed: 10/27/1999
  • Issued: 12/19/2006
  • Est. Priority Date: 10/27/1998
  • Status: Expired due to Term
First Claim
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1. A decoder for producing a synthesized wideband signal, comprising:

  • a) a signal fragmenting device for receiving an encoded version of a wideband signal previously down-sampled during encoding and extracting from said encoded wideband signal version at least pitch codebook parameters, innovative codebook parameters, and linear prediction filter coefficients;

    b) a pitch codebook responsive to said pitch codebook parameters for producing a pitch codevector;

    c) an innovative codebook responsive to said innovative codebook parameters for producing an innovative codevector;

    d) a combiner circuit for combining said pitch codevector and said innovative codevector to thereby produce an excitation signal;

    e) a signal synthesis device including a linear prediction filter for filtering said excitation signal in relation to said linear prediction filter coefficients to thereby produce a synthesized wideband signal, and an oversampler responsive to said synthesized wideband signal for producing an over-sampled signal version of the synthesized wideband signal; and

    f) a high-frequency content recovering device comprising;

    i) a random noise generator for producing a noise sequence having a given spectrum;

    ii) a spectral shaping unit for shaping the spectrum of the noise sequence in relation to linear prediction filter coefficients related to said down-sampled wideband signal; and

    iii) a signal injection circuit for injecting said spectrally-shaped noise sequence in said over-sampled synthesized signal version to thereby produce said full-spectrum synthesized wideband signal.

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