| 摘要 |
PURPOSE:To eliminate the need for the addition of a counter, even if the frame is long, by opening a gate with a final frequency dividing value, when a desired period is larger than the maximum frequency dividing value, in a frequency divider used for the production of a frame pulse. CONSTITUTION:An operating circuit 26 stores a variable M in its inside and the initial value of the variable M is taken as the final frequency dividing ratio N. The operating circuit 26 references the variable M in synchronizing with the count end pulse outputted from the counter 21, feeds the next calculating value, subtracts the preset value given from the variable M to counters 21-23 so that the period N in total is counted at the counters 21-23. When the variable M is M>2L, the counters 21-23 feed a preset value being the period L, and when M<=2L, the counters 21-23 feed the preset value being the period M. The frequency divider is controlled that the count end pulse of the counters is outputted externally only once per the period N. |
