Line bar generator

EE 50 July/August 1986 A B Bradshaw 5 line bar generator 0 12V/80 mA 2 20k 6 IC1 IC2a 56p IC2b 37 11 7k 7 4R1P3144 R30 10k 2 I0On • see text C 4,7p, C>_ The video signal transmitted by most TV broadcast stations is rather com- plex. For most tests and experiments, however, a fairly simple signal will suffice. The circuit presented here provides a small, inexpensive source of line synchronizing pulses and line bar. The first of the three timers in the diagram provides 4.7 is sync pulses. It is arranged as an astable multi- vibrator with a period of 64 Ms. The rising (here: negative-going) edge of the sync pule triggers a second timer. The width of the output pulse of this timer determines the position 120p C8 C3 10n 7 To IC1 = 555 R4 IC2a,IC2b = 556 82k C4 C6 C7 710n R5 IEEE 12V C4 ° BC5 47 R8 R6 7 R9 75f/ 11 aox 1t..134IS{,H of the line bar. The line bar proper is provided by the third timer. To obtain a usable video signal, the sync and bar signals must be added, which takes p...