Three channel audio transmission and/or reproduction systems
AssigneeSony Broadcast & Communications Limited
InventorRichard F. Schiller
Life of this patent
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Abstract
In order to permit three-component (left, right and back) audio signals (LS, RS, BS) to be conveyed by a three-channel (left, right and mono) transmission system and still permit stereo and mono compatibility, the signals are encoded so that the three channels carry LS-1/2BS, RS-1/2BS and LS+RS+BS, respectively. Upon receipt, the signals can be decoded back to LS, RS and BS respectively. In a mono receiver without such a decoder, the signal LS+RS+BS on the mono channel is employed, and in a stereo receiver the signals LS-1/2BS and RS-1/2BS on the stereo channels are employed.
Claims14
In a method of transmitting an audio signal having a left stereo component, a right stereo component and a back component using a transmitting system having left, right and mono channels, the steps of:
- forming a composite mono signal by adding said left stereo component, said right stereo component and said back component;
- forming a composite left signal and a composite right signal from respective differences between said left stereo component and said back component, and between said right stereo component and said back component;
- and
- transmitting said composite mono signal, said composite left signal and said composite right signal over said mono, left and right channels, respectively.
An encoder for encoding a three-component signal having a left stereo component signal, a right stereo component signal and a back component signal for transmission by a three-channel system having a left stereo channel, a right stereo channel and a mono channel, said encoder comprising:
- first forming means for forming a composite left signal for said left stereo channel of said three-channel system from said left stereo component signal and said back component signal with a respective weight ratio of approximately 1:-1/2;
- second forming means for forming a composite right signal for said right stereo channel of said three-channel system from said right stereo component signal and said back component signal with a respective weight ratio of approximately 1:-1/2;
- and third forming means for forming a composite mono signal for said mono channel of said three-channel system from said left stereo component signal, said right stereo component signal and said back component signal with substantially equal weights.
A decoder for decoding a composite left signal, a composite right signal and a composite mono signal respectively received on left, right and mono channels of a three-channel signal receiving system, said decoder comprising:
- means for producing a left stereo component signal by combining the composite left, mono and right signals with relative weightings of approximately 3:1:-1, respectively;
- means for producing a right stereo component signal by combining the composite right, mono and left signals with relative weightings of approximately 3:1:-1, respectively;
- and means for producing a back component signal by combining the composite mono, left and right signals with relative weightings of approximately 2:-2:-2, respectively.
Dependencies are inferred from the claim text.