| 摘要 |
PROBLEM TO BE SOLVED: To quickly lock a frequency by generating a voltage pertinent to a channel frequency, comparing the size of the voltage with the size of the voltage outputted from a loop filter and deciding the voltage to be supplied to a voltage controlled oscillator(VCO) by the result. SOLUTION: A frequency/phase detector 1, the loop filter 2, a VCO control part 100 and the VCO 3 are closed-loop connected. The channel data of N bits (N is an optional natural number) by the channel frequency decided corresponding to an operated external system are converted and the signals of a prescribed level pertinent to the channel frequency are generated. The level of the generated signals and the level of the signals outputted from the loop filter 2 are compared, the output signals of the loop filter 2 are outputted when the levels are equal and the generated signals are outputted when the levels are different. Thus, the frequency is locked when feedback is performed for one time in a loop. |
