| 摘要 |
PURPOSE:To unify the oscillator and selection circuit, by using the phase locked loop circuit as the frequency oscillation circuit and changing the selective frequency through the use of memory, in the circuit selecting r sets of arbitrary frequencies among n sets of frequencies. CONSTITUTION:nCr code signal (a) and nCr set signal (b) are inputted as the address and chip selection to the read only memory 8 as the frequency selection input and the data of the memory 8 is set as the input to the program counter 7. Next, the self-running frequency output of the voltage controlled oscillator 6 is frequency- divided with the value of the counter 7 and it is given to the phase detector 4 as the phase comparison wave, phase comparison is made with the standard frequency of the main oscillator 3 and control is made so that the phase of the phase comparison wave and the standard wave can be equal with the closed loop of the oscillator 6 and the low pass filter 5. The r sets of selective frequencies have equal stability as the main oscillator 3 after a given time. |
