| 摘要 |
PURPOSE:To prevent a mixture of a through signal from a VHF circuit during UHF reception and a desired signal from becoming a disturbing signal by coupling a resistance between a Bu power line during UHF reception and a BH and BL power line during VHF reception. CONSTITUTION:The coupling resistance 1 between Bu and BH is set to 1-20kOMEGA, and when a voltage is impressed to Bu, a slight voltage is also impressed to BH to turn on diodes 5-7 for band switching, and devices of an OSC and an RF circuit are not driven. Therefore, the UHF circuit is placed in high channel mode during VHF reception and a disturbing signal of frequency double as high as IF frequency among received disturbances transmitted from the VHF circuit is reduced. |
