Digital encoder for door operator

Claim 1

A digital radio control system for actuating a controlled device in response to the transmission and receipt of a digitally coded signal consisting of a series of pulses each having one of two possible timing characters representing digit values and comprising: a selectively operable digital pulse sequence transmitter comprising a free-running oscillator, a pulse timing circuit connected to said oscillator, a recycling counter having plural outputs equal in number to the number of pulses in the sequence to be transmitted, a plurality of two-position switches connected between respective counter outputs and said pulse timing circuit for controlling oscillator pulse timing according to the state of each two-position switch as the counter output associated therewith is activated, means connecting the oscillator to the counter to advance and recycle same, whereby said transmitter produces a repeating series of time modulated pulses, the individual timing characters of which are determined by the conditions of said two-position switches; said control system further including a receiver having a radio transmission pulse input means, a second recycling counter having plural outputs equal in number to the number of pulses in said series to be transmitted and received, a second plurality of two-position switches connected to respective outputs of said second counter to be actuated thereby as said counter is advanced, a pulse generator connected to said radio pulse input means to produce a pulse for each radio pulse received by said input, means connecting said radio transmission pulses to said second counter to advance same, second timing control means connected to said second pulse generator to control the timing of said generated pulses therefrom, the two-position switches being commonly connected to the second timing control means for controlling the timing of said pulses therefrom in accordance with the settings of said second two-position switches, comparator means having two inputs and an output, the inputs being connected to receive the radio transmitted pulses and the locally generated pulses from said pulse generator and for comparing the timing values thereof, the output being connected to said second counter for resetting same in the event of a non-coincidence of pulses applied to the inputs of said comparator means, an output means connected between said second counter means and said controlled device to actuate same only if said second counter is advanced through at least one full cycle by a coincidence of pulses applied to the respective inputs of said comprator means during said repeating radio pulse transmission cycle.