FALSE VIDEO SIGNAL GENERATOR USING BOTH NTSC AND PAL/ SECAM SYSTEMS

摘要

PURPOSE:To obtain the corresponding video signals from the same false video signal generator in a PCM device, by using a changeover input between NISC and PAL/SECAM and selecting the changeover input. CONSTITUTION:The clock pulse generated from an oscillator 11 is supplied to a horizontal synchronizing counter 12, and a pulse is delivered to a horizontal synchronism to be supplied to a vertical synchronizing counter 13. The count values corresponding to each other and selected by the NTSC-PAL/SECAM changeover input supplied from a changeover input terminal T13 are supplied to the clear terminal of the counter 13 via a selector 14. The output of the counter 13 is supplied to a selector 15 and a decoder 16, and the digital input is supplied to the decoder 16 through the terminal 11. The outputs of the selector 15 and the decoder 16 are supplied to an FF17, and the signals produced in accordance with the NTSC or PAL/SECAM system are synthesized through a multiplexer 18. Then the false video signal corresponding to the changeover input supplied from the terminal 13 is obtained through the terminal 12.