| 摘要 |
PURPOSE:To prevent deterioration of C/N of an other signal processor when the broadcast wave is discontinued and also to prevent a user of the terminal from mistaking the C/N deterioration for a trouble of the community facilities. CONSTITUTION:A VHF band input amplifying part 6a of a signal processor 2a converts the VHF band TV broadcast signal of an input terminal 4a into an intermediate frequency signal and amplifies this signal at an intermediate frequency amplifier part 10a. This amplified signal is supplied to a VHF band output amplifier part 18a via a changeover switch 12a, converted into a desired frequency at the part 18a, and supplied to a transmission line of the community facilities. The level of the intermediate frequency signal received from the part 6a is detected by a detection circuit 28a, and the intermediate frequency signal is supplied to a switching control circuit 30a. When the broadcast wave is discontinued and the level of the intermediate frequency signal is reduced, the circuit 30a switches the switch 12a. Thus the information signal produced by an intermediate frequency modulator 26 and supplied via a 4-distributor 24 is supplied to the part 18a. The modulator 26 is also used in common for other signal processors 2b and 2c.
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