Electrical audio signal processing systems and devices – Binaural and stereophonic
Patent
1987-11-24
1989-02-07
Isen, Forester W.
Electrical audio signal processing systems and devices
Binaural and stereophonic
381 2, H04S 100
Patent
active
048037273
ABSTRACT:
A stereo coding system is described in which 7 kHZ bandwidth sum (L+R) and difference (L-R) signals are converted to digital form (11 and 12). The difference signal is then bandlimited (13) to 2 kHZ and downsampled (14) to 4K samples/sec prior to being encoded (16), and the sum signal is encoded (15); both are then multiplexed together (17) prior to transmission. After reception, the signal is demultiplexed (19) and the difference signal is decoded (20) upsampled (21) to its original bit rate and filtered to prevent aliasing (22), and the sum signal is delayed in a digital buffer (28) and decoded (24) prior to both being converted back to analogue form (23 and 25). The delay introduced by the digital buffer (28) equalizes the excess delay introduced into the difference signal.
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Holt Christopher E.
Rollett John M.
British Telecommunications public limited company
Isen Forester W.
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