Remote control system

Claim 2

A remote control system, comprising a transmitter including a carrier oscillator for producing a radio frequency carrier signal, modulation oscillation means for modulating said carrier signal with modulation frequency signals in the high audio frequency range, pulse generator means for producing repetitive pulses at a predetermined repetition rate corresponding to a low audio frequency range, means connected to said pulse generator means and operable by said pulses for repetitively changing the frequency of said modulation frequency signals between first and second substantially different modulation frequencies in the high audio range, a receiver including an input circuit for receiving and demodulating said carrier signal thereby producing first and second tone signals alternating at the pulse generator rate, an output control device, and means for actuating the output control device electricallY connected between the input circuit and the output control device, said actuation means impressing an actuating signal on the output control device only responsive to audio signals of the frequency of the first and second modulation frequencies which alternate between the first and second modulation frequencies at the rate of the pulse generator.

Claim 3

A remote control system, comprising a transmitter including a carrier oscillator for producing a radio frequency carrier signal, modulation oscillation means for modulating said carrier signal with modulation frequency signals in the high audio frequency range, pulse generator means for producing repetitive pulses at a predetermined repetition rate corresponding to a low audio frequency range, means connected to said pulse generator means and operable by said pulses for repetitively changing the frequency of said modulation frequency signals between first and second substantially different modulation frequencies in the high audio range, a receiver including an input circuit for receiving and demodulating said carrier signal to produce first and second repetitively alternating tone signals at the first and second different modulation frequencies, first means operable by one of said tone signals for producing positive control pulses, second means operable by the other tone signal for producing negative control pulses, an integrating capacitor, charging means connected from said first and second means to said integrating capacitor for charging said capacitor with said positive and negative control pulses, first and second electronic switching means having respective control input electrodes connected in common to said integrating capacitor, an energy storage capacitor, an output control device, first output means connecting said first electronic switching means to said energy storage capacitor for charging said energy storage capacitor through said first electronic switching means in response to integrated pulses of one polarity across said integrating capacitor, and second output means for connecting said second electronic switching means between said energy storage capacitor and said output control device for discharging said energy storage capacitor into said output control device in response to integrated pulses of the opposite polarity across said integrating capacitor, said integrating capacitor preventing actuation of said output control device in response to tone signals alternating at a repetition rate substantially greater than the predetermined repetition rate.

Claim 4

A remote control system, comprising a transmitter including a carrier oscillator for producing a radio frequency carrier signal, modulation oscillation means for modulating said carrier signal with modulation frequency signals in the high audio frequency range, pulse generator means for producing repetitive pulses at a predetermined repetition rate corresponding to a low audio frequency range, means connected to said pulse generator means and operable by said pulses for repetitively changing the frequency of said modulation frequency signals between first and second substantially different modulation frequencies in the high audio range, a receiver including an input circuit for receiving and demodulating said carrier signal to produce first and second repetitively alternating tone signals at the first and second different modulation frequencies, first means operable by one of said tone signals for producing positive control pulses, second means operable by the other tone signal for producing negative control pulses, an integrating capacitor, charging means connected from said first and second means to said integrating capacitor for charging said capacitor with said positive and negative control pulses, first and second electronic switching means having respective control input electrodes connected in common to said integrating capacitor, an energy storage capacitor, an output control device, first output means connecting said first electronic switching means to said energy storage capacitor for charging said energy storage capacitor through said first electronic switching means in response to integrated pulses of one polarity across said integrating capacitor, and second output means for connecting said second electronic switching means between said energy storage capacitor and said output control device for discharging said energy storage capacitor into said output control device in response to integrated pulses of the opposite polarity across said integrating capacitor, said integrating capacitor preventing actuation of said output control device in response to tone signals alternating at a repetition rate substantially greater than the predetermined repetition rate.

Claim 5

A system according to claim 2, including a discharging resistor connected to said energy storage capacitor to prevent operation of said output control device in response to tone signals having a repetition rate substantially less than the predetermined repetition rate.

Claim 6

A transmitter for a remote control system, comprising a carrier frequency signal source, modulation means for modulating said source with a modulation frequency signal, said modulation means including an oscillator with a resonant circuit for determining the modulation frequency, at least one reactance element, and a free-running pulse generator including at least one electronic switch rendered alternatively conductive and non-conductive at a predetermined repetition rate, means connecting said reactance element and said electronic switch in a series circuit across said resonant circuit, said electronic switch thereby alternately connecting and disconnecting said reactance element into and from said resonant circuit to change the tuning thereof and thereby change said modulation frequency signal between two different modulation frequencies at said predetermined repetition rate.

Claim 7

A transmitter for a remote control system, comprising a carrier frequency signal source, modulation means for modulating said source with a modulation frequency signal, said modulation means including an oscillator with a resonant circuit for determining the modulation frequency, at least one reactance element, and a free-running pulse generator including at least one electronic switch rendered alternatively conductive and non-conductive at a predetermined repetition rate, means connecting said reactance element and said electronic switch in a series circuit across said resonant circuit, said electronic switch thereby alternately connecting and disconnecting said reactance element into and from said resonant circuit to change the tuning thereof and thereby change said modulation frequency signal between two different modulation frequencies at said predetermined repetition rate.