| 摘要 |
<p>The monitor, for a test coder/decoder, in PCM TDM telephony prevents faulty registration when comparing the original test signal with the same test signal obtained by sampling and in general attenuated and delayed. A comparator (V) compares a test signal (Up) with exponential decay with samples of the same test signal received via a coder (C), decoder (D) and amplitude regulator (AR). The comparator output is used to control the amplitude regulator and is also passed on to a threshold circuit (S1, S2) for comparing with references. The result of the comparison determines whether an alarm is released or not.</p> |
