| 摘要 |
PURPOSE:To achieve high-precision frequency digital conversion and frequency analog conversion without any adjustment, by converting a frequency value directly into a digital value by using a frequency comparing circuit, a multiplier, etc. CONSTITUTION:An input pulse signal S1 is differentiated by a digital differentiating circuit 11 to obtain a sample 1. On the basis of the count value of an M-notation up-down counter 13, pulses whose number is proportional to that of input pulses are generated and passed through an M-notation rate multiplier 15, a timing generating circuit 14, etc., to obtain a sample 2. Then, a frequency comparator 12 makes a pulse-number comparison between the samples 1 and 2 and on the basis of their difference, the counter 13 is driven to obtain an output digital signal S4 at an output terminal 4. The pulse-number output of the M-notation rate multiplier 15, ob the other hand, is passed through a low-pass filter 16 after the level adjustment of a variable resistor 17 to obtain an output analog signal S3 at a terminal 3. This constitution achieves high-precision frequency digital conversion and frequency analog conversion without any adjustment. |
