| 摘要 |
<p>The generator for generating test call signalto test a subscriber's circuit has a reduced size. The generator comprises a pulse generator for generating call signal having constant period, an amplifier for amplifying the call signal to have a designated amplitude, an input filter for eliminating the noise incoming through input terminal, a voltage level changing unit for changing the level of input voltage, and a power supply for rectifying and filtering the level changed voltage to provide power to the pulse generator and the amplifier.</p> |
