TRANSMITTER CIRCUIT

• US 3,796,958 A
• Filed: 07/14/1972
• Issued: 03/12/1974
• Est. Priority Date: 07/14/1972
• Status: Expired due to Term

• Current Assignee: John R. Reeves, Paul M. Johnston, Raymond W. Mackenzie
• Original Assignee: John R. Reeves, Paul M. Johnston, Raymond W. Mackenzie
• Inventors: Johnston, Paul M., MacKenzie, Raymond W., Reeves, John R.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US05/271,880
• Time in Patent Office: 606 Days
• Field of Search: 325/105,111,113,119,145,152,185,186,163,139 331/173,178 332/16,17 340/171R,214,224
• US Class Current: 375/306
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence

Abstract

The invention pertains to an improved transmitter circuit design which responds to a DC input pulse by generating an AC signal of a predetermined frequency and exhibiting a pulse width corresponding to the pulse width of the DC input pulse. The AC signal is used to frequency modulate an RF carrier signal and the resulting frequency modulated RF carrier signal is transmitted for remote reception by a radio receiver circuit which functions to recover the original AC signal and pulse width information.

Claims

1. In a transmitter apparatus for generating an FM modulated AC output waveform in response to a DC input pulse, the combination of, modulator means adapted to respond to said DC input pulse by generating an AC output signal of a predetermined frequency of a duration corresponding to the pulse width of said DC input pulse, oscillator means operably connected to said modulator means for producing a continuous AC waveform which is frequency modulated by said AC output signal from said modulator means and means operatively connected to said oscillator means for transmitting said frequency modulated AC output signal.

2. In a transmitter apparatus as claimed in claim 1 wherein said means includes an audio frequency oscillator for developing said AC output signal and means operably connected between said modulation means and said oscillator means to concentrate the energy of the AC output signal at a predetermined frequency.

3. In a transmitter apparatus as claimed in claim 1 wherein said oscillator means comprises a Colpitts configuration having an input and an output and including means for developing negative feedback between said output and said input to provide improved stability and reduced amplitude modulation.

4. In a transmitter apparatus as claimed in claim 2 wherein said means for concentrating the energy of said AC output signal consists of an integrating circuit.

5. In a transmitter apparatus for generating an FM modulated AC output waveform in response to a DC input pulse developed in a coil of a magnetic pulse generator, the combination of a Zener diode regulator connected in a series arrangement with the coil of the magnetic pulse generator and adapted to respond to electrical pulses developed by said coil by generating a regulated DC pulse of the width corresponding to the width of the pulse developed by said coil, modulator means adapted to respond to said DC pulse produced by said Zener diode regulator by generating an AC signal of a predetermined frequency and of a duration corresponding to the pulse width of said DC pulse, and RF oscillator means operably connected to said modulator means for producing an RF carrier signal which is frequency modulated by said AC signal to produce a continuous RF signal containing information identifying the pulses developed by the magnetic pulse generator.