Signal detector with echo cancellation

• US 6,731,747 B2
• Filed: 02/23/2001
• Issued: 05/04/2004
• Est. Priority Date: 02/23/2001
• Status: Active Grant

• Current Assignee: Alpha Industries Incorporated (Skyworks Solutions Incorporated)
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Klein, Jeffrey D., Beamish, Norman J.
• Primary Examiner(s): Harvey, Minsun Oh
• Assistant Examiner(s): Harold, Jefferey
• Application Number:
  US09/792,816
• Publication Number:
  US 20020118821A1
• Time in Patent Office: 1,166 Days
• Field of Search: 379/386, 379/215.01, 379/283, 379/373.01, 379/373.02, 379/351, 379/142.04
• US Class Current: 379/386
• CPC Class Codes: H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers

Abstract

A system is disclosed for accurately detecting an alert signal. Improving detector accuracy decreases missed detects and false detects. In one example embodiment the detector monitors received telephone signals for an alert signal such as a CPE alert signal. In such a configuration, the invention processes the received signal prior to monitoring by the detector to remove or reduce unwanted echo, interference and/or other signal portions that may otherwise inhibit accurate detection of alert signals sent from a remote location. In one configuration, the invention performs echo suppression or cancellation on the received signal to eliminate or reduce echo, such as may be introduced by a hybrid.

Claims

1. An customer premise alert signal (CAS) receiver system, comprising:

an echo canceller configured to connect to an input line and an output line and generate a processed signal, where the input line carries a received signal and the output line carries a transmitted signal such that the signal processor receives the received signal and the transmitted signal;

a detector configured to receive the processed signal and detect a CAS signal as part of the processed signal, the processed signal comprising a processed version of the received signal from the echo canceller;

a receiver connected to the input line, where the receiver is selectively controllable between an on-state and an off-state, and wherein the receiver is configured, when in the on-state, to receive a caller-ID information; and

a controller, in communication with the detector and the receiver, the controller configured to activate the receiver from the off-state to the on-state upon detection, by the detector, of an CAS signal.

2. The system of claim 1, wherein the echo canceller comprises a finite impulse response filter.

3. The system of claim 1, wherein the receiver comprises a receiver configured to receive and demodulate frequency shift key modulated signals.

4. The system of claim 1, wherein the receiver, when in an off-state, consumes less power than when the receiver is in the on-state.

5. A method for detecting an alert signal sent from a remote location and receiving information from the remote location, comprising:

receiving an input signal on an input line, the input signal including unwanted signal portions;

processing the input signal to remove the unwanted signal portions of the input signal to create a processed signal;

monitoring the processed signal to detect an alert;

responsive to detection of the alert, turning on a receiver from an inactive state to an active state to thereby allow the receiver to receive the alert signal, an information signal, or both; and

receiving the information signal with the receiver.

6. The method of claim 5, wherein the alert comprises a customer premise alert signal.

7. The method of claim 5, wherein the monitoring is performed by an alert detector embodied in a digital signal processor.

8. The method of claim 5, wherein processing the input comprises filtering the input.

9. The method of claim 5, wherein processing the input comprises performing echo cancellation and the unwanted signal portion comprises near end echo.

10. The method of claim 5, wherein the method is performed in a telephone.

11. An customer premise alert signal (CAS) and an information signal receiver system, comprising:

means for generating a processed signal, the means for generating connected to an input line and an output line, where the input line carries a received signal and the output line carries a transmitted signal;

means for receiving the processed signal and detecting an CAS signal as part of the processed signal, the processed signal comprising a processed version of the received signal from the means for generating a processed signal;

said means for receiving connected to the input line and connected to the means for receiving and detecting, where the means for receiving selectively receives the information signal when the means for receiving and detecting detects an alert signal; and

means for controlling the means for receiving, wherein responsive to a signal from the means for receiving and detecting, the means for controlling selectively turns on the means for receiving to an active status.

12. A system for detecting an customer premise alert signal (CAS), comprising:

means for filtering configured to isolate echo from a combined signal comprised of a received signal and echo;

means for combining configured to subtract the output of the means for filtering from the combined signal; and

means for detecting configured to receive the output of the means for combining and monitor for an CAS signal; and

means for activating a receiver, the means for activating a receiver configured to turn on a receiver in response to detection of the CAS signal by the means for detecting.