×

Methods of testing multifrequency dialing signals

  • US 4,398,147 A
  • Filed: 04/15/1981
  • Issued: 08/09/1983
  • Est. Priority Date: 04/15/1981
  • Status: Expired due to Term
First Claim
Patent Images

1. A method of testing the frequency of a signal, which comprises the steps of:

  • (a) feeding a standard signal having a known amplitude through a signal preparation circuit to determine any gain or loss in amplitude as the signal is being fed through the signal preparation circuit;

    (b) processing an unprocessed signal through the signal preparation circuit wherein the unprocessed signal is being prepared to test the frequency thereof;

    (c) adjusting the amplitude of the processed signal by an amount equal to the determined gain or loss of the amplitude of the standard signal;

    (d) determining whether the adjusted amplitude of the processed signal exceeds a predetermined threshold amplitude value;

    (e) measuring, from a precise time of the unprocessed signal, the time interval required by a preset number of cycles of the unprocessed signal, in response to the determination that the adjusted amplitude of the processed signal exceeded the predetermined threshold amplitude value, to provide an indication of the frequency of the unprocessed signal; and

    (f) comparing the measured time interval with a preset time interval to provide an indication as to whether the frequency of the unprocessed signal is an acceptable frequency.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×