Stereo demultiplexer
AssigneeSony International (Europe) GmbH
InventorJens Wildhagen
Life of this patent
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Abstract
For the noise reduction of an audio signal generated by stereo-demultiplexing of a frequency-modulated stereo multiplex signal (SFM(t)) a filtering within the signal path to generate the stereo difference signal (ud(t)) is performed that determines a weight with which the upper sideband (ud,u(t)) and the lower sideband (ud,l(t)) of the amplitude modulated stereo-difference signal are weighted with different weighting factors that are dependent on the frequency.
Claims25
A method for demultiplexing a stereo multiplex signal, comprising the steps of:
- single sideband demodulating said stereo multiplex signal so as to obtain an upper sideband signal of an amplitude modulated stereo difference signal of said stereo multiplex signal;
- single sideband demodulating said stereo multiplex signal so as to obtain a lower sideband signal of said stereo difference signal;
- filtering said upper sideband signal in accordance with a first filter transfer function;
- and
- filtering said lower sideband signal in accordance with a second filter transfer function that is different from said first filter transfer function.
A method for demultiplexing a stereo multiplex signal, comprising the steps of:
- filtering said stereo multiplex signal in accordance with a filter transfer function that applies a first weighting factor to an upper sideband signal of an amplitude modulated stereo difference signal of said stereo multiplex signal and a second weighting factor that is different from said first weighting factor to a lower sideband signal of said stereo difference signal;
- and
- coherently demodulating said filtered stereo multiplex signal so as to obtain said stereo difference signal.
A stereo demultiplexer for demultiplexing a stereo multiplex signal, comprising:
- single sideband demodulating means configured and adapted for single sideband demodulating said stereo multiplex signal so as to obtain an upper sideband signal of an amplitude modulated stereo difference signal of said stereo multiplex signal;
- single sideband demodulating means configured and adapted for single sideband demodulating said stereo multiplex signal so as to obtain a lower sideband signal of said stereo difference signal;
- filtering means configured and adapted for filtering said upper sideband signal in accordance with a first filter transfer function;
- and
- filtering means configured and adapted for filtering said lower sideband signal in accordance with a second filter transfer function that is different from said first filter transfer function.
A stereo demultiplexer for demultiplexing a stereo multiplex signal, comprising:
- filtering means configured and adapted for filtering said stereo multiplex signal in accordance with a filter transfer function that applies a first weighting factor to an upper sideband signal of an amplitude modulated stereo difference signal of said stereo multiplex signal and a second weighting factor that is different from said first weighting factor to a lower sideband signal of said stereo difference signal;
- and
- coherent demodulating means configured and adapted for coherently demodulating said filtered stereo multiplex signal so as to output said stereo difference signal.
Dependencies are inferred from the claim text.