Independent hysteresis apparatus for tone detection

Details Independent hysteresis apparatus for tone detection Independent hysteresis apparatus for tone detection

1991-07-15

1993-10-05

Dwyer, James L.

Telephonic communications

Supervisory or control line signaling

Signal receiver

379381, 379377, 381 46, 36472409, H04M 100

Patent

active

052512568

ABSTRACT:
To detect tones for call progress monitoring, hysteresis apparatus is provided whereby the output of a typical tone detector such as a comparator operating in conjunction with a selective filter is monitored by a counter. The counter is incremented and decremented according to whether the input is indicative of the presence or absence of a tone. If the counter reaches a predetermined count within a given period of time, then an indication is made that the tone exists. If the counter does not reach this predetermined count or threshold within the applicable time, then it is an indication that the tone does not exist. The thresholds of the counters plus the amount by which a counter may be incremented or decremented for each input signal is variable for each tone. In this manner a plurality of different tones on a common communications channel such as a telephone line can be continuously monitored even though each tone may be very close in frequency and the particular communications channel being monitored may be subjected to various types of noise.

REFERENCES:
patent: 4405833 (1983-09-01), Cave et al.
patent: 4439639 (1984-03-01), Munter
patent: 4528664 (1985-07-01), Cheng et al.
patent: 4534041 (1985-08-01), Munter
patent: 4696031 (1981-09-01), Freudberg et al.
patent: 4805212 (1989-02-01), Hase et al.
patent: 5007000 (1991-04-01), Baldi
patent: 5063593 (1991-11-01), Kwon

Affiliated with

Also associated with

Rating

Independent hysteresis apparatus for tone detection does not yet have a rating. At this time, there are no reviews or comments for this patent.

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

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1011234