| 摘要 |
A compatible four channel system primarily for use in conjunction with a radio transmission system for transmitting four individual audio signals over a medium having primary and secondary information channels and first and second auxiliary information channels, the primary and secondary channels carrying information that is consistent and compatible with existing monophonic and stereo-phonic standards. More particularly, the primary information channel carries a signal representing the sum of SQ-encoded composite signals LT and RT the secondary information channel carries a signal representing the difference between LT and RT, and the first and second auxiliary channels carry auxiliary signals T and Q, respectively, which each contain, to the extent they are present, equal reduced-amplitude proportions of the four individual audio signals in predetermined angular relationships which exhibit an equal angular relationship respecting corresponding signals in composite signals representing the sum and difference of LT and RT, respectively. The T signal is utilized in a receiver/decoder to diminish "unwanted" signals in the four individual audio signals, and the Q signal may additionally be used to effect virtual cancellation of such "unwanted" signals.
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