Telephone exchange circuit with PCM signal level measuring - has PCM word adaptors in level meter and adder for summation of square PCM word values

摘要

The circuit is for telephone exchanges in which AF signals are transmitted by pulse code modulation (PCM) techniques. To test the signal channels, PCM, AF test signals, of at least one preset AF level are transmitted and received by a level measuring device which contains an adaptor (A). The latter comprises the square value of an amplitude value, corresponding to the respective PCM word. The level measuring device has an adder (B), into which are supplied and summated the corresp. square values, when the PCM words are received. The receiving is limited by a counter (C). The level measuring device has a second adaptor containing output values formed by the adder under control of the counter. These values represent the respective level value of the adder summation. Pref. the output values are each a decadic logarithm of the square roots of the respective summation value.