| 摘要 |
<p>PURPOSE:To attain the measurement of various performance of the entire circuit at a base station and also to simplify the constitution of an end office equipment, by transmitting the carrier frequency of the wave transmitted from the base station after converting it into a reception frequency of the base station and monitoring the circuit at the base station. CONSTITUTION:The radio frequency signals transmitted successively from a base station 20 via radiotelephony repeaters 3 are led to an end office 30 and supplied to a return test device 10 via a branching filter 4 to be mixed the oscillation frequency of a crystal oscillator there. This mixed frequency signal is converted to be equal to the reception frequency of the station 20 and then sent back to the filter 4. The signal sent to an LCX8 via the filter 4 is relayed and amplified by the repeaters 3 and sent successively to the station 20. The return signal reached the station 20 is supplied to a supervisory unit 2 by a direction coupler 7. The unit 2 decides the presence or absence of the return signal, the distortion of a modulated signal and the circuit quality of S/N, etc. Thus the overall quality of the circuit is decided.</p> |
