| 摘要 |
PURPOSE:To easily discriminate which range of frequency an input signal belongs to even when it has a high frequency, by using a decoder having simple constitution and a counter detecting the change in output of the decoder. CONSTITUTION:A decoder DEC sets its output D1 at 1 by one cycle of a clock CK1 when counted value Q1-QN of a counter CNT1 reaches TXf1 equivalent to a frequency f1. An output D2 is set at 1 likewise when the counted value Q1-QN reaches TXf2. In this way, Dn is set at 1 when the counted value reaches TXfn within one interval T. When any one of the outputs D1-Dn is set at 1, the output of an NOR gate turns to be 0 and is counted by a counter CNT2. The interval of sectioned frequencies f1-fn can be set arbitrarily, and the counted value of the counter CNT2 shows how many sectioned frequencies f1...fn the counted value of the counter CNT1 clears at each point of time, and it is retained by a latch circuit RT and taken out as an output 1-M. |
