Histogram for controlling a telephone
A telephone is operated in accordance with a histogram of data taken from the operation of one of its components, such as an echo cancelling circuit. The histogram provides a variable threshold for comparison with other signals or a variable control signal.
1 . A method for producing a control signal, said method comprising the steps of:
sampling the difference in magnitude between the output and the input of an electronic circuit having a variable transfer function;
accumulating a plurality of differences and producing a histogram thereof; and
reading the number of samples in a predetermined group in the histogram to produce the control signal.
2 . A method for producing a control signal in a telephone having an echo cancelling circuit, said method comprising the steps of:
sampling the difference between the output and the input of the echo cancelling circuit having a variable transfer function;
accumulating a plurality of differences and producing a histogram thereof; and
reading the number of samples in a predetermined group in the histogram to produce the control signal.
3 . The method as set forth in claim 2 and further including the step of:
comparing the control signal with another signal.
4 . The method as set forth in claim 2 and further including the step of:
applying the control signal to the control input of a variable gain amplifier.
5 . The method as set forth in claim 2 and further including the step of:
applying the control signal to the control input of a multiplex circuit.