Appeal No. 96-0273
Application No. 08/246,387
claim 7 was amended. Claims 11 and 12 have been found to be
allowable over the prior art of record.
The disclosed invention relates to a method and system
for detecting the presence of a Supervisory Audio Tone (SAT)
superimposed on a voice/data signal.
Claims 1 and 9 are illustrative of the claimed invention,
and they read as follows:
1. A method for detecting the presence of a Supervisory
Audio Tone (SAT) when the SAT is superimposed on a Frequency-
Modulated (FM) voice/data signal to yield a combined signal
which is periodically sampled, comprising the steps of:
(a) receiving successive samples of the combined
voice/data and SAT signal such that noise associated with said
combined
signal is suppressed and the combined signal is captured when
the signal power of the combined signal exceeds the power of
the noise and the combined signal is suppressed and the noise
is captured when the power of the noise exceeds the power of
the combined signal;
(b) deleting the voice/data signal from a sample
containing the combined voice/data and SAT signal so that only
the SAT remains:
(c) determining the signal power of the SAT;
(d) determining the noise power of the SAT, the SAT
noise power moving in an opposite direction from the SAT
signal power; and
(e) comparing the signal power to the noise power of the
SAT to determine if the signal power of the SAT exceeds the
noise power of the SAT as occurs when the SAT is present.
2
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