| 摘要 |
PURPOSE:To measure the making rate of a dial pulse by a digital method with simple constitution by executing the arithmetic processing of the difference between a braking period and a making period in the number of times of sampling of dial pulses and the total number of times of sampling. CONSTITUTION:Dial pulses are received from a terminal 30 and counted by a pulse counting circuit 31. Simultaneously, a timing generating circuit 32 generates a timing clock to sample the dial pulses with a fixed time interval. When a level deciding circuit 36 decides that the sampled dial pulses are in the low level, the sampled dial pulses are sent to a ''+1'' adder 37 to count up the number of times of sampling in the braking period, and when in the high level, the sampled dial pulses are sent to a ''-1'' adder 38 to count up the number of times of sampling in the making period. The difference between the number of times of sampling in the braking period and that of the making period in the whole dial pulses is obtained as an output of an adder 39. The total number of times of sampling of the whole dial pulses is obtained from a sampling counting circuit 42 and the making rate is obtained from an arithmetic processor 40. |
