| 摘要 |
<p>A cable line quality evaluating method for evaluating a quality of a cable line for transmitting a digital modulation signal in a bidirectional manner comprises the steps of extracting a noise signal of an upstream line from one of a cable line connection point for evaluating a head end of the cable line evaluated in the quantity and the cable line evaluated in the quantity and a connection point between a tap-off and the cable line evaluated in the quality, generating a pseudo random signal, modulating a carrier signal of its predetermined frequency by means of the pseudo random signal, and then outputting the modulated signal as a test carrier, outputting an output signal obtained by adding the noise signal of the upstream line and the test carrier, selectively receiving the signal of its predetermined frequency from the output signal, and modulating the selectively received signal, and comparing the modulated signal with the pseudo random signal in bits, and then measuring a bit error rate. <IMAGE></p> |
