Patent GB-1451787-A (GB)
Title: Remote control receivers
IPC: H04N5/00
Filed: 1973-10-09
Abstract: 1451787 Controlling by sound: remote control for TV receivers SONY CORP 9 Oct 1973 [12 Oct 1972] 46966/73 Heading G4F and G4H [Also in Division H3] In a remote control receiver for remotely controlling an apparatus in response to a remote control signal having two different frequency components arranged in a predetermined order of time, the different frequency components are selected at 15a, 15b, Fig. 3, first and second memories 27a, 27b memorize one and the other selected output signals from 15a, 15b, a first gate 30a gates an output of the first memory in response to the other of the selected output signals from 16b and a second gate 30b gates an output of the second memory in response to the one of the output signals from 16a Operation of push-buttons 1 and 2, Fig. 1 in a remote control transmitter control the power switch and channel selector of a television receiver. When the control switch 1 is made on monostable multi-vibrators 3 and 4 operate to control oscillators 9 and 10 so as to transmit an ultrasonic wave signal from a speaker 12 including a pulse (P3), Fig. 2 (not shown) of frequency fl and a pulse (P5) of frequency f2. Similarly if control switch 2 is made on the output signal is composed of a pulse of f2 and a pulse of fl. At the remote control receiver Fig. 3, the signal fl is selected from the wave received from a microphone 13 and amplifier 14 in a BPF 15a. After a delay determined by a resistor and capacitor 23R and 23C in a noise eliminating circuit 17 a transistor 24 turns on so as to enable detecting circuits 16a 16b to operate. A differentiating circuit 28 provides reset of memory flip-flops 27a, 27b so that the detected signal fl remaining after this reset operation sets the memory 27a. Now if the signal f2 is detected by BPF 15b and detector 16b the memory 27b is set and the output from an AND gate 29 together with the output from the detector 16b turn transistor 30a on to give a 'O' output at 31a corresponding to detection of the control signal fl followed by f2. The remote control receiver circuit operates similarly to a control signal f2 followed by fl which sets memory 27b and then memory 27a to turn on a transistor 30b and provide a 'O' output at 31b. In a modified remote control receiver Fig. 6 (not shown) the two different signal channels fl, f2 are fed from the amplifier 14 via a common emitter follower (32). Each channel comprises a BPF (33a, 33b), a detector (34a, 34b), a noise eliminating circuit (45a, 45b) and a flip-flop (35a, 35b) feeding a respect AND gate (36a, 36b) the other input of which is from the output of the noise eliminating circuit of the other channel. The outputs of the detector circuits (34a, 34b) control a reset circuit (48) for resetting the flip-flops (35a, 35b). The noise eliminating circuits (45a, 45b) each include a normally on transistor (43) which is turned off by an input control signal and a RC time constant circuit (44R, 44C) which does not allow intermittent signals such as noise to turn on a transistor (47a) in the associated flip-flop as do the selected control signals. A '1' output at (37a) is obtained for an f1 followed by an f2 signal whereas a '1' output is obtained at (37b) for the opposite sequence control signal.