FREQUENCY DISCRIMINATING DEVICE

摘要

PURPOSE:To make it possible to discriminate the frequency with high precision by correcting the decode value of a counter by the number of clocks corresponding to the clock input prohibition period in a frequency generating signal measurement counter. CONSTITUTION:An edge detection circuit 6 detects the edge of a signal Sp from a frequency generating signal generator 2 and outputs a signal Se. A latch circuit 13 latches the discrete value of a counter 11 with a signal Se. A clock input signal prohibition circuit 7 prohibits the input of a clock Ck to the counter 11 for the period of n-many clocks Ck from the input of the signal Se in order to stop the counting operation of the counter 11 while latching. A delay circuit 9 resets the counter 11 after the period of n-many clocks Ck is over and the counting operation is started. Then, when the discrete value of the counter 11 gets to the count value corresponding to the delay time, the counter 11 is reset and the actual counting operation is started.