Telephonic communications – Supervisory or control line signaling – Signal receiver
Patent
1991-12-31
1995-08-15
Dwyer, James L.
Telephonic communications
Supervisory or control line signaling
Signal receiver
379283, 34082573, H04M 300
Patent
active
054426960
ABSTRACT:
The present invention provides a method and apparatus for detecting control signal information for an element of a communication system. The control signal information is included in one or more segments of a signal communicated over a communication system channel. The invention provides for the application of a plurality of tapers to a segment of a communicated signal; the transformation of a tapered segment; the determination of a similarity score based on a transform of a tapered segment and a model of a control signal; the identification of control signal information based on a similarity score; and the creation of an indicator signal representative of the identified control signal information to the communication system element. The control signal information may comprise a dual-tone multi-frequency signal. The tapers may comprise a discrete prolate spheroidal sequence. A similarity score may be determined based on a ratio of energy distributions. The numerator of the ratio may comprise an energy distribution based on a control signal model, and the denominator of the ratio may comprise an energy distribution based on a difference between a transformed tapered segment and the control signal model.
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Lindberg Craig R.
Thomson David J.
AT&T Corp.
Brown Kenneth M.
Dwyer James L.
Restaino Thomas A.
Shehata M.
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