Telephonic communications – Supervisory or control line signaling – Signal receiver
Reexamination Certificate
2006-03-28
2006-03-28
Harold, Jefferey F. (Department: 2646)
Telephonic communications
Supervisory or control line signaling
Signal receiver
C379S283000, C379S093280
Reexamination Certificate
active
07020272
ABSTRACT:
A signal classifier decomposes a subject signal into subbands. The signal classifier then analyzes the subbands for a presence of energy and uses detection logic to classify the energy as being representative of a frame of a signal using one of the following protocols: DTMF, MF-R1, ANS (V.25), LEC-DIS, V.21, or AA (i.e., telephone, facsimile, or modem). The detection logic is expandable to detect future protocols. The classifier may employ a preclassifier to select a reduced number of notch filters from among plural notch filters at frequencies which sinusoidal signals composing the energy in the subbands of the protocols may be found. A look-up table having predetermined ranges of data corresponding to the frequencies of the sinusoidal signals may be used to reduce calculation times. By splitting the subject signal into subbands and using efficient filters, the classifier uses an order of magnitude fewer processor instruction cycles than previous classifiers. The classifier is useful in inter-networking devices, such as a media gateway, to facilitate telephony services, such as VoIP.
REFERENCES:
patent: 5119322 (1992-06-01), Stroobach
patent: 5353346 (1994-10-01), Cox et al.
patent: 5392348 (1995-02-01), Park et al.
patent: 5428680 (1995-06-01), Murata et al.
patent: 5619564 (1997-04-01), Canniff et al.
Mitra, S.K. and Hirano, K., “Digital All-Pass Networks,”IEEE Trans. Circuits Systs., CAS-21(5): 688-700 (1974).
Tanrikulu, O. and Kalkan, M., “Design and Discrete Re-optimization of All-pass Based Power Symmetric IIR Filters,”Electronics Letters, 32(16): 1458-1460 (1996).
Tanrikulu, O., “Adaptive Signal Processing Algorithms with Accelerated Convergence and Noise Immunity,” Ph.D. Thesis, Imperial College of Science, Technology and Medicine, University of London (1995).
Valenzuela, R.A and Constantinides, A.G., “Digital Signal Processing Schemes for Efficient Interpolation and Decimation,”IEE Procedings-G, Circuits Devices and Systems, 130(6): 225-235 (1983).
Vaidyanathan, P.P., “Multi-rate Systems and Filter Banks,”Prentice-Hall(1993).
Tanrikulu, O., et al., “Finite-Precision Design and Implementation of All-Pass Polyphase Networks for Echo Cancellation in Sub-Bands,” ICASSP-95, Detriot, USA, 4:3039-3042 (May, 1995).
Tanrikulu, O{hacek over (g)}uz, “High-Density DTMF, MF-R1, MF-R2 Detection,”Media Technologies Group, pp. 1-8.
Hamilton Brook Smith & Reynolds P.C.
Harold Jefferey F.
Tellabs Operations Inc.
LandOfFree
High density signal classifier for media gateways does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High density signal classifier for media gateways, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High density signal classifier for media gateways will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3579271