| 摘要 |
PROBLEM TO BE SOLVED: To provide an in-building CATV system, where a terminal uses an up-converter to convert the frequency of an incoming signal into a high frequency and a down-converter at a connecting point to an external CATV system converts the incoming signal with the high frequency into the incoming signal with the original frequency, that allows external CATV systems with different specifications to use a device transmitting a reference signal used by each converter for the frequency conversion to a transmission line. SOLUTION: The down-converter 10 is provided with a reference oscillation circuit 36 that generates the reference signal for the frequency conversion and transmits the reference signal to the transmission line L of the terminal via a BPF 41 and an LPF 42. Furthermore, the transmission line for the reference signal in the down-converter 10 is provided with an attenuator 43 of a variable attenuation type to adjust the level of the reference signal. As a result, the up-converter 20 of the terminal uses the same reference signal as that of the down-converter 10 for the frequency conversion and the up-converter 20 can transmit the reference signal at a proper level. |
