×

Filter for voice operated triggering circuits

  • US 4,156,797 A
  • Filed: 08/04/1978
  • Issued: 05/29/1979
  • Est. Priority Date: 08/04/1978
  • Status: Expired due to Term
First Claim
Patent Images

1. In combination in a system for energizing a transmitter keying relay in response to pulses occurring at the frequency of audio input pulses:

  • high pass filter circuit means responsive to said pulses;

    delay circuit means responsive to said pulses for delaying said pulses for a predetermined time period;

    low pass filter circuit means responsive to said pulses delayed for a predetermined time period;

    bandpass filter circuit means coupled between said high pass filter circuit and low pass filter circuit means, said bandpass filter circuit means having an output terminal connected to a bandpass switching circuit means; and

    monostable retriggerable multivibrator circuit means coupled between said bandpass switching circuit means and output means including an inhibit line output terminal and switching means for providing said transmitter keying relay energizing signals to key the transmitter continuously when audio input signals having frequencies in a predetermined passband are present and for a given time period after said audio input signals are no longer present.

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