Patent GB-1508360-A (GB)
Title: Channel tuning and indicating arrangements
IPC: H04N5/445
Filed: 1975-07-02
Abstract: 1508360 Channel indicator for TV receivers SONY CORP 2 July 1975 [5 July 1974] 27937/75 Heading H3Q In a channel tuning and indicating arrangement including a channel selector 5, T 0 -T 9  connected at 7 to an electronic tuner (not shown), a channel indicator 31 is connected to a memory 12, address input terminals 12a of the memory are connected to an address signal generator 11 which is connected to the channel selector 5, data input terminals 12b are connected to a data signal generator 14 which is connected to channel selector switches S 0 -S 9  and a switch 8, 9 connected to switches S 0 -S 9  enables selection of (i) a channel selecting mode so that the switches S 0 -S 9  control the channel selector and (ii) a channel number programming mode so as to enable reprogramming of a channel number for the indicaton in the memory. With switch 8 off and switch 9 contacting 9b by closing a switch such as S 0  a pulse generator 1 drives a counter 4 until the output O 0  of a B-D decoder 5 becomes O. This selects an associated tuning voltage circuit T 0  which tunes the electronic tuner at 7 to the channel 12 associated with switch. S 0 . Since the output O 0  of decoder 5 becomes O the output of a D-B encoder 11 becomes (0000) and data (0001) and (0010) programmed at the address (0000) of random access memories 12 and 13 are obtained at their outputs 12e, 13e so as to display the received channel 12 in 7 segment LED displays 31, 32. The channel received may be stepped by sequential operation of a switch 2a of a pulse generator 2. The selected tuning voltage circuit T 0  is adjusted to the required channel, say 12, by adjustment of V 0 . The memories 12, 13 are initially programmed to store the channel number 12 for the display associated with the O output O 0  corresponding to the switch S 0  by closing switch 8 and moving switch 9 contact 9a to contact 9c. The output from encoder 11 provides a (0000) address signal, corresponding to the O output from decoder 5, to address inputs 12a, 13a of memories 12, 13. Now by operating a switch S, an output from a flip flop 18 to a write input 12c of 12 enables an output from a D-B encoder 14 corresponding to the '1' tens digit of the display to be read into the data input 12b of 12. Operation of a further switch S2 causes an output from a flip flop 19 to a write input 13c of 13 enables an output from the encoder 14 corresponding to the '2' units digit of the display to be read into the data input 13b of 13. If an error is made then by closing switch 25 the flip flops 18, 19 can be reset and then a new programme can be written into 12, 13 for display. The other switches S 1 -S 9  similarly select tuning voltage circuits T 1 -T 9  (not shown) similar to T 0  and address channel display memories 12, 13 to provide the appropriate channel display at 31, 32. When the output of memory 12 is (1111) the output of a nand circuit 33 functions to blank or suppress an unnecessary '0' display signal from the tens indicating device 31. The memories 12, 13 are always supplied with voltage from a battery so that the memories are not cleared when the TV power supply is switched off. Also the memories can be non-volatile.