Digital tone decoder

Details Digital tone decoder Digital tone decoder

1975-03-19

1977-04-05

Claffy, Kathleen H.

H04M 150

Patent

active

040163709

ABSTRACT:
A decoder is disclosed for use in a communication system wherein bits of information are conveyed by the transmission, on a communication line, of code tones of distinctive frequencies each corresponding to a respective bit of information. The decoder divides an incoming signal into repetitive intervals having durations dependent on the period of the signal and provides digital measurements of the length of the interval by counting clock pulses during each interval. The digital measurements are then processed to test for persistence of the signal at a stable frequency for a predetermined time and for matching of said stabilized frequency to a recognized code tone frequency. More specifically, such decoder is disclosed as part of a larger decoder for use in, for example, a telephone communication system wherein dial numbers or other characters are communicated by way of simultaneously transmitted code tone pairs.

REFERENCES:
patent: 3454720 (1969-07-01), Minchenko
patent: 3537001 (1970-10-01), Friend
patent: 3790720 (1974-02-01), Schartmann
patent: 3912869 (1975-10-01), Ullakko

Affiliated with

Also associated with

Rating

Digital tone decoder does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Digital tone decoder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital tone decoder will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2267170