Telephonic communications – Supervisory or control line signaling – Signal reception at substation
Patent
1997-08-27
1999-05-04
Isen, Forester W.
Telephonic communications
Supervisory or control line signaling
Signal reception at substation
379377, 379382, 379418, 324 7644, H04M 322, G01R 23165
Patent
active
059012196
ABSTRACT:
A reduced complexity method of ring signal detection, in which a digital signal processor monitors an incoming data stream for zero crossings and employs a limiter-discriminator to differentiate ring frequency signals from line noise. Controlled noise is injected into the incoming data stream in order to prevent false declarations of ring signals in the presence of low frequency natural noise or low amplitude signals. The method conserves valuable processing power and may therefore prove useful in DSP-based telephone devices that must simultaneously perform multiple processing operations such as ring detection and speech processing.
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3Com Corporation
Isen Forester W.
Saint-Surin Jacques M.
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