| 摘要 |
PURPOSE:To improve the practical arrival distance of the voice FM transmitter mounted on an on-vehicle television receiver detecting a non-selection antenna input from an antenna selection signal of a diversity antenna controller and applying an FM wave output to the nonselection antenna input. CONSTITUTION:An antenna selection signal is at a high level in an active state and one of four signals for both a latch period and a comparison period of an antenna input is controlled to be high and the three signals are controlled to be low. An antenna selection switching element whose antenna selection signal corresponding to a high level is activated, its antenna input is electrically connected to a tuner input 14, other antenna selection switching elements are reverse-biased by a resistor 16e and cut off to isolate electrically the antenna input from the tuner input 14. As a result, an FM wave is supplied from three elements in four elements of the diversity antenna at all times without giving adverse effect onto reception sensitivity of a television receiver. |
