| 摘要 |
A receiver apparatus adapted to have coupled thereto intentionally transmitted signals, each being characterized as having a predetermined number of pulsations, which are transmitted over a communication link such as the standard switched telephone network and, at times, noise signals which are introduced into the communication link. The receiver includes measuring means arranged to measure the time interval between successive signals coupled thereto, and signal verification means to verify that each signal coupled to the receiver is either an intentionally transmitted signal or a noise signal. In the event that a noise signal is coupled to the receiver, the signal verification means is arranged to abort measurements of the measuring means. Measurements not aborted are indicative of the time interval between each two successive intentionally transmitted signals coupled to the receiver. |
