| 摘要 |
PURPOSE:To allow an IC circuit to generate an optional synchronizing signal system among five kind of color television systems, by composing the IC circuit of a digital circuit while removing a time constant circuit, etc., for a crystal oscillator and a VCO connected to a frequency generator. CONSTITUTION:The output of the frequency generator 1 is inputted to a frequency divider 2 and a programmable counter 4. The output of the VCO7 is inputted to a 1/2 frequency divider 9 and a programmable counter 8. The outputs of the programmable counters 4 and 8 are supplied to a phase comparator 6 to make a phase comparison and the output of it is supplied to the VCO7. The output of the 1/2 frequency divider 9 is supplied to a frequency divider 10 and a logical circuit 11, whose outputs are supplied directly to a logical circuit 14 and supplied to a logical circuit 13 through a programmable counter 12. The output of the logical circuit 13 is also supplied to the logical circuit 14. Then, the logical circuits 11, 13, and 14 output various synchronizing signals. |
