To provide a communication apparatus capable of automatically observing the frequency characteristics of noises on telephone lines.
A calculation controller 4 turns a switch circuit SW1 to off. A spectrum analyzer 6 measures the frequency spectrum of a noise N1 appearing on the input of a receiver 3. The calculation controller 4 turns the switch circuit SW1 to on, the spectrum analyzer 6 measures the frequency spectrum of a noise N2 appearing at the input of the receiver 3, the calculation controller 4 subtracts the frequency spectrum of the noise N1 from that of the noise N2 to calculate the frequency spectrum of a noise N3. Thus the frequency characteristics of the noises on telephone lines can be automatically observed to reduce the labor for measuring the noises.
UEDA MASAMI
SUMITOMO ELECTRIC NETWORKS INC
Toshio Morita
Yoshihei Nakamura
Yutaka Horii
Hisato Noda
Masayuki Sakai