Radio control transmitter which suppresses harmonic radiation

• US 4,806,930 A
• Filed: 05/02/1988
• Issued: 02/21/1989
• Est. Priority Date: 08/01/1986
• Status: Expired due to Term

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: Chamberlain Manufacturing Corporation (General Dynamics Corporation)
• Inventors: Wojciak, Bernard J. Jr.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US07/188,645
• Time in Patent Office: 295 Days
• Field of Search: 340/825.69, 340/696, 455/114, 455/129, 331/77, 331/105, 331/117 D
• US Class Current: 340/12.5
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence

Abstract

A radio control transmitter which suppressed harmonics includes an oscillator which is coded by code selecting switches and in which undesired harmonics are reduced from the output of the transmitter by adding inductors into the emitter, the collector or the base of the radio frequency oscillator.

Claims

1. A coded radio frequency transmitter for remote control comprising, a transmit switch, an encoder connected to said transmit switch, code selector switches connected to said encoder, a radio frequency oscillator which oscillates at the desired radiation frequency connected to the output of said encoder and including a transistor amplifier and a first inductor connected in the emitter, collector or base circuit of said transistor so as to produce a high impedance to harmonics of said desired radiation frequency, wherein said first inductor is in the emitter circuit of said transistor amplifier, and including a second inductor which causes a high impedance to harmonics of said desired radiation frequency connected in the base circuit of said transistor.

2. A coded transmitter according to claim 1 including a third inductor which causes a high impedance to harmonics of said desired radiation frequency connected in the collector circuit of said transistor.

3. A coded radio frequency transmitter for remote control comprising, a transmit switch, an encoder connected to said transmit switch, code selector switches connected to said encoder, a radio frequency oscillator which oscillates at the desired radiation frequency connected to the output of said encoder and including a transistor amplifier and a first inductor connected in the emitter, collector or base circuit of said transistor so as to produce a high impedance to harmonics of said desired radiation frequency, wherein said first inductor is in the emitter circuit of said transistor amplifier, and a second inductor which causes a high impedance to harmonics of said desired radiation frequency connected in the collector circuit of said transistor.

4. A coded transmitter according to claim 3 including a third inductor which causes a high impedance harmonics of said desired radiation connected in the collector circuit of said transistor.