| 摘要 |
PURPOSE: A variable frequency band attenuator for improving frequency sensitivity of a broadband broadcasting relay apparatus is provided to extend a broadcasting relay region and improve quality of broadcasting by preventing re-transmission of spurious frequencies. CONSTITUTION: Broadcasting signals are distributed by using a distributor(2). A mixer(3) receives the broadcasting signals. An intermediate frequency is determined by a local signal generated from a frequency synthesizer(8). An intermediate frequency module(4) passes the broadcasting signals of a lower band and removes the broadcasting signals of an upper band by using a band pass filter. A mixer(6) outputs the broadcasting signals without spurious signals. The intermediate frequencies of the broadcasting signals inputted to a mixer(9) are determined by the local signal of a frequency synthesizer(13). An intermediate frequency module(10) passes the broadcasting signals of the upper band and removes the broadcasting signals of the lower band by using the band pass filter. A mixer(12) outputs the broadcasting signals without the spurious signals. |
