| 摘要 |
PURPOSE:To make peripheral parts unnecessary and also to reduce an input/ output pin by constituting a titled filter by use of a reference signal generating means, a magnitude discriminating means, a frequency dividing means, a gate means, an up-down counter and a detecting means. CONSTITUTION:A digital signal input signal D1 and a reference digital signal D2 are used as an input of a magnitude sicriminating means 6 and magnitude is discriminated. Signals S1, S2 showing a magnitude relation of the signal D1 and D2 becme inputs S5, S6 of an up-down counter 9 together with an output S4 of a frequency dividing means 7, and a digital signal D3 of a binary number is obtained from the counter 9. The means 7 divides an inputted clock pulse S3, and generates and outputs a clock pulse of frequency being proportional to an absolute value of a difference between the signal D2 and the input D1, and it becomes a clock input of the counter 9. Also, in order to prevent overflow and underflow of the counter 9, the maximum value and the minimum value are detected by detecting means 10, 11, and the gate outputs S5, S6 of the signals S1, S2 are inhibited by controlling a gate means 8 by outputs S7, S8. In this way, no perkpheral parts are required. |
