| 摘要 |
PURPOSE:To accurately recognize the echo fault generated in a telephone exchange by providing a burst signal duration detecting means and a signal level measuring means or the like to a receiver side equipment so as to measure the receiver echo level quantatively in two-wire line. CONSTITUTION:A control section 33 of a receiver equipment detects a burst signal from an output signal of an amplifier 31, gives a level 1 as a selection control signal when the signal amplitude is a prescribed level or over to a signal selection section 32, which cuts off a signal passing during the level 1. Then a selection signal output 36 from a variable attenuator 35 and a comparison signal output 37 being a branched output of the amplifier 31 are given to a level meter 39 via a switch 38 and the attenuator 35 is adjusted so as to make the deflection of the meter 39 equal by switching the switch 38. As a result, even if the switch 38 is switched, the meter 39 shows no change in deflection, the sum of the gain of the amplifier 34 and the gain of the attenuator 35 is a relative level of echo. Thus, the echo level is measured quantatively and the echo fault is accurately recognized.
|
