Electrical audio signal processing systems and devices – Binaural and stereophonic – Broadcast or multiplex stereo
Patent
1987-03-25
1988-06-21
Isen, Forester W.
Electrical audio signal processing systems and devices
Binaural and stereophonic
Broadcast or multiplex stereo
H04H 500
Patent
active
047529555
ABSTRACT:
The compatibility of an FM stereophonic broadcasting system incorporating companding of the difference signal, in which both the usual difference signal and a compressed version of the difference signal are transmitted, with conventional FM receivers is improved by minimizing crosstalk from the compressed difference signal to the usual difference signal that sometimes occurs in conventional FM stereo receivers, particularly when the multiplex signal is received under multipath propagation conditions. Crosstalk in conventional receivers is significantly reduced, without an attendent lessening of perceived noise reduction in the companded system, by inverting the phase of the audio signals contained in the compressed difference signal relative to the audio content of the usual difference signal, and also adjusting the relative amplitudes of different portions of the audio frequency spectrum of the compressed difference signal in approximate correspondence with the response of the human hearing mechanism to sound loudness level. In the receiver of the companded system the relative amplitudes of the audio signals contained in the spectrum of the received compressed difference signal are restored to have the levels they had before adjustment at the transmitter, and their phase inverted to put them in phase with corresponding audio signals in the received uncompressed difference signal, and then expanded complementarily with the compression characteristic utilized at the transmitter.
REFERENCES:
patent: 3594506 (1971-07-01), Bauer et al.
patent: 4388493 (1983-06-01), Maisel
patent: 4485483 (1984-11-01), Torick et al.
patent: 4534054 (1985-08-01), Maisel
patent: 4602380 (1986-07-01), Stebbings
patent: 4602381 (1986-07-01), Cugnini et al.
patent: 4704727 (1987-11-01), Beard
T. Bossert, "Impairments to VHF/FM Reception in Motor Vehicles Caused by Multipath Propagation and Possibilties for Improving Receivers", EBU Review-Technical, No. 205, Jun. 1944, pp. 111-116.
Broadcast Technology Partners
Isen Forester W.
Olson Spencer E.
LandOfFree
FM stereophonic system having improved compatibility in presence does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with FM stereophonic system having improved compatibility in presence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and FM stereophonic system having improved compatibility in presence will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-934051