Apparatus and method for the identification of specially encoded

Details Apparatus and method for the identification of specially encoded Apparatus and method for the identification of specially encoded

1979-03-12

1981-07-28

Olms, Douglas W.

Multiplex communications

Wide area network

Packet switching

179 1GB, 370110, 455 70, H04H 500

Patent

active

042812178

ABSTRACT:
A sub-audible in-band tone system is disclosed for identifying an FM stereophonic radio broadcast which is specially encoded, as with dynamic range improvement encoding or quadraphonic encoding, for example, A constant frequency pilot tone is added at a low level (e.g. at -70dB) to the transmitted signal at or near the upper frequency limit of the audio frequency spectrum (15 kHz). The audio spectrum is not notched or otherwise altered to accommodate the tone. FM stereophonic receivers detect the pilot tone by heterodyning the received tone with a stable mixing signal at 15.2 kHz derived from the 19 kHz FM stereo pilot tone. The shifted frequency tone is passed to a low frequency narrow band detector which can control a visual display and switch in appropriate signal decoding circuitry when the tone is detected.

REFERENCES:
patent: 2617923 (1952-11-01), Rekart
patent: 3061783 (1962-10-01), Noller
patent: 3845391 (1974-10-01), Crosby
patent: 3867700 (1975-02-01), Wycoff
patent: 3908090 (1975-09-01), Kahn
patent: 4016366 (1977-04-01), Kurata

Affiliated with

Also associated with

Rating

Apparatus and method for the identification of specially encoded does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Apparatus and method for the identification of specially encoded, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for the identification of specially encoded will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-550505