| 摘要 |
PURPOSE:To synthesize an arbitrary frequency without any problem on the accuracy and secular change, by integrating a unit electrical angle determined with a designated frequency information and a clock signal used for audio recognition. CONSTITUTION:A clock signal generating circuit 5 consisting of a quartz oscillator and others, outputs a clock frequency in (x)Hz. Information in a desired frequency (f) is inputted to a PROM circuit 1, a unit electrical angle DELTAtheta(=360 deg. f/x) is read out and outputted. A full adder 3 inputs the electrical angle DELTAtheta outputted from the circuit 2, it is added with the integrated electrical angle stored in a temporary storage circuit 4, and the result of addition is taken as a new integrated electrical angle and fetched to the circuit 4 with the signal timing from a circuit 5. Thus, if nothing is stored in the circuit 4, the circuit 3 outputs the DELTAtheta and 2DELTAtheta at second, and it restores to the initial state after the addition of the most significant bit (MSB) repetitively. Disired frequency can be synthesized from the bit output of the MSB. |
