GB1511016A - Selectro system - Google Patents

Abstract

1511016 Selector system for TV channel selector TEXAS INSTRUMENTS Inc 14 May 1975 [22 May 1974 (3)] 20427/75 Heading H3Q [Also in Division G41 A system for selectively energizing one of 2<SP>n</SP> devices 92a-92p or 93a-93p comprises (a) input terminals A, B, (b) output terminals O, P, (c) 2<SP>n-</SP><SP>1</SP> additional output terminals D-K, and (d) an nstage binary counter 21 operative in response to and during the application of an input signal (e.g. 0) to A or B to produce a signal (e.g. 1) alternately at O, P and to produce through a decoder 22 a signal (e.g. 1) at terminals D-K one at a time in a first sequence when said input signal is applied to A and in the reverse sequence when it is applied to B; each terminal D-K being connected to a unique pair of said devices 92, 93 and each terminal O, P being connected to a respective one of said pair. As described, the system is part of a TV channel selector operable directly through switches 81a-81p or by remote control to connect a potentiometer 92 to a voltage controlled tuner, and to actuate a channel indicator (e.g. neon bulbs) 93. In the remote control mode, input A or B is grounded (switch 62), causing counter 21 (flip-flops I-IV) to count clock pulses 23 up or down respectively. The outputs of the least significant bit flip flop I form "odd" and "even" outputs O, P while the higher order outputs from flip flops II-IV are decoded at 22 to give a 1-out-of-eight signal D-K; O, P and D-K define the selected channel uniquely. Remote control is stopped when the desired channel is reached. In the direct control mode a switch 81a-81h or a switch 81i-81p is pressed so as to ground input A or B according as an even or an odd channel is required (e.g. 81f or 8 In for channels 10 or 11). The counter counts up or down as before until that output line (e.g. 65 for I) is reached which corresponds to the pair of channels (e.g. 10/11) containing the one selected, at which point a '1' level is fed back to the counter via A or B to stop it; Counting up or down ensures that the correct output O or P is selected as well as (e.g.) output I. The outputs D-K and O-P are fed to analog switches IC 902 A-D, Fig. 5 (not shown); each output O, P selects a pair of switches, while each output D-K selects an input within that pair. This results in the selection of a unique one of 16 outputs of the switches for a potentiometer 92 and an indicator 93 corresponding to the desired channel. The counter may be operated at two different clock rates according as the command is a remote or direct one; the former mode requires a slower speed to provide reaction time for the operator to discontinue the command signal, while the latter mode is effectively instantaneous. A detailed circuit diagram is also provided (Fig. 4, not shown).