Patent GB-1066932-A (GB)
Title: Improvements relating to subscription television systems
Inventor: WHITE LOUIS STUART
IPC: H04N7/16
Filed: 1963-08-27
Abstract: 1,066,932. Recording television channels used. BRITISH TELEMETER HOME VIEWING Ltd. Aug.24, 1964 [Aug. 27, 1963], No. 33925/63. Heading H3Q.  Each receiver in a subscription television system has an attachment comprising a pricing mechanism, opinion survey facilities as in Specification 1,066,931, selector means for selecting one of a number of priced or unpriced channels, and a recording device operated by a motor energized through contacts closed in response to timing signals received over the system network. The attachment is energized through contacts operated by a relay in the mains lead to the receiver, and the timing signals pass through a tone-detector, amplifier and delay valve to the relay which operates the recorder motor. The transmitter produces separate pricing demand and control signals. At definite intervals (e.g. every half-hour) both these signals are simultaneously interrupted and the control carrier is transmitted at full amplitude.. An opinion survey can be carried out after any programme, and an opinion recording is made when the subscriber presses a button. First embodiment.-Each half-hourly signal is followed by a time-identification code, and the relay operates the recorder for a definite time. When the tape is removed from the attachment the total length represents the number of halfhours of operation of the receiver. Any priced channels viewed will be identified by their corresponding identification signals on the tape, and the part of the tape not so marked will represent viewing of unpriced channels. Second embodiment.-To identify which of two unpriced channels has been viewed at any time each such channel is allotted an identifying frequency for recording, e.g. 50 c/s. and 100 c/s. When the receiver is switched to the lowerfrequency unpriced channel a low-pass filter with cut-off just above the carrier frequency of this channel is inserted in the aerial lead of the receiver and simultaneously a 50 c/s signal is applied to the recording head. At half-hourly intervals, the recording motor is operated for a short time to make a 50 c/s. recording. Similarly, for the other unpriced channel, a highpass filter with cut-off just below the carrier frequency of this channel is inserted in the aerial lead and the 100 c/s. signal is recorded. The identification signals of the priced channels are transmitted for two seconds each half-hour as before, and will be recorded if the receiver has been tuned to one of them. Third embodiment.- To show which parts of a particular programme or advertisement have been watched, an extra carrier is transmitted carrying time-code signals comprising on/off bursts whose sequence changes according to a binary progression, e.g. fifteen pulses whose order is altered every three minutes. These pulses are recorded after the 50 c/s. or 100 c/s. signals representing unpriced channels or after blank tape when priced channels are being viewed. A recording is also made on switching on or changing from one channel to another. The delay valve feeding the relay of the recording motor also allows a recording to be made to indicate switching off of the receiver.