Digital radio control

Abstract

A digital radio control system comprising a transmitter and receiver wherein a plurality of two position switches may be set in a transmitter to pick a particular code which will be serially transmitted by the transmitter and in which a plurality of switches in a receiver may be set to a particular code such that if the same code is selected in the receiver as is set in the transmitter the receiver will be energized upon recognition of the code. Such transmitters and receivers are adaptable to many applications, as for example, garage door actuators; and due to the large number of possible code combinations, interference between other control units within radio frequency range will not occur.

I claim as my invention: 
     
       1. A coding system for a transmitter and receiver so that a selected receiver will respond to a particular transmitter comprising a transmitter capable of transmitting a RF signal in a binary code having pulses having time lengths T1 and T2 of different times, means at said transmitter for setting said binary code to a selected combination, a receiver tuned to said RF signal, and including code comparing means receiving the incoming binary code, means at said receiver for setting a binary code to a selected combination supplying an input to said code comparing means, output means actuated by said comparing means if said means for setting a binary code at the transmitter and receiver are set to the same code combination, wherein said means at said transmitter for setting said binary code includes a plurality of two position switches, a shift register connected to said plurality of two position switches, an oscillator to drive said shift register, divider means connected to said oscillator and to said shift register to reset it, a two pulse length generator connnected to said shift register and to said dividers to produce said binary code and a RF oscillator connected to said two pulse generator and keyed thereby to cause it to radiate said binary code. 
     
     
       2. A coding system according to claim 1 including means to cause said transmitter to transmit said binary code signal a number of times with a time interval between succeeding transmissions including a switch connected for keying said RF oscillator. 
     
     
       3. A coding system according to claim 1 wherein said means at said receiver for setting a binary code comprises a plurality of two position switches. 
     
     
       4. A code system according to claim 3 including a threshold circuit connected to the input of said code comparing means and passing only signals which exceed a preset amplitude. 
     
     
       5. A coding system according to claim 3 wherein said code comparing means comprises a shift register into which received incoming code signals are supplied and a plurality of gates receiving inputs from said shift register and said two position switches to produce an output when said incoming code signals are the same as the code set by said two position switches. 
     
     
       6. A coding system according to claim 5 comprising means for resetting said shift register so as to receive incoming signals. 
     
     
       7. A coding system according to claim 6 including a correct code counter and memory circuit receiving the outputs of said plurality of gates and recording the number of correct incoming sequential signals and connected to said output means to energize it. 
     
     
       8. A coding system according to claim 7 including timing means connected to said correct code counter and memory circuit to reset it to zero at discrete time intervals. .Iadd. 9. A coding system for a transmitter and receiver so that a selected receiver will respond to a particular transmitter comprising a transmitter capable of transmitting a RF signal in a binary code having pulses, means at said transmitter for setting said binary code to a selected combination, a receiver tuned to said RF signal, and including code comparing means receiving the incoming binary code, means at said receiver for setting a binary code to a selected combination supplying an input to said code comparing means, output means actuated by said comparing means if said means for setting a binary code at the transmitter and receiver are set to the same code combination, wherein said means at said transmitter for setting said binary code include n number of two position switches to produce 2 n  possible codes, a shift register connected to said plurality of two position switches, an oscillator to drive said shift register, divider means connected to said oscillator and to said shift register to reset it, a pulse generator connected to said shift register and to said dividers to produce said binary code and a RF oscillator connected to said pulse generator and keyed thereby to cause it to radiate said binary code and wherein said means at said receiver for setting a binary code includes second n number of two position switches to produce 2 n  possible codes. .Iaddend.