PULSE POSITION MEASUREMENT TYPE METER-DRIVING CIRCUIT CAPABLE OF IMPROVING MEASUREMENT ACCURACY

摘要

A pulse control circuit generates latch signals in response to edges of externally-input pulses and generates a resetting signal after each of the latch signals is generated. A pulse position measurement counter counts reference clock signals, thereby measuring the time interval between the generation of one latch signal and the generation of the succeeding latch signal. In response to the latch signal, a latch circuit latches the time interval measured by the pulse position measurement counter as output data. A pulse detector detects that the time interval between successive latch signals is shorter than a predetermined time. It also detects that the number of latch signals which have been input is larger than a predetermined number. A data control circuit is employed in association with the pulse detector. The data control circuit supplies a control signal to the pulse control circuit after the lapse of a predetermined time from the detection performed by the pulse detector, thereby interrupting a counting operation performed by the pulse position measurement counter before detection of a next latch signal.