Method and apparatus for transmitting sigma delta modulated audio signals
AssigneeSony Corporation
InventorAyataka Nishio
Life of this patent
Estimating the term…
Abstract
When transmitting a sigma-delta modulated signal produced from plural channel signals through a sigma-delta modulator, the main channel is made to have a different sampling frequency from the sub channel, for enhancing transmission efficiency.
Claims8
A signal transmitting apparatus for transmitting a sigma-delta modulated signal produced by performing sigma-delta modulation with respect to each signal of multi-channel signals composed of at least two channels, the apparatus comprising:
- first modulating means for sigma-delta modulating signals of one group of said multi-channel signals at a first sampling frequency substantially higher than an audio band frequency;
- second modulating means for sigma-delta modulating signals of another group of said multi-channel signals at a second sampling frequency, said second sampling frequency being substantially higher than said audio band frequency but lower than said first sampling frequency;
- mixing means for mixing a digital signal output from said first modulating means with a digital signal output from said second modulating means;
- and
- means for transmitting a mixed digital signal produced by said mixing means.
A signal transmitting method for transmitting a sigma-delta modulated signal produced by performing sigma-delta modulation with respect to each channel signal of multi-channel signals composed of at least two channels, comprising:
- a first step of sigma-delta modulating a signal of one group of said multi-channel signals at a first sampling frequency substantially higher than an audio band frequency;
- a second step of sigma-delta modulating a signal of another group of said multi-channel signals at a second sampling frequency substantially higher than the audio band frequency but lower than said first sampling frequency;
- a third step of mixing a digital signal produced at said first step with a digital signal produced at said second step and producing a mixed digital signal;
- and
- a fourth step of transmitting said mixed digital signal.
Dependencies are inferred from the claim text.