| 摘要 |
PURPOSE:To improve the tracking error from a low frequency to a medium frequency, by applying a correcting voltage only to a voltage variable reactance element of a high frequency tuning circuit at a band from a low to a medium tracking frequency. CONSTITUTION:When a receiving frequency is the low frequency tracking frequency, transistors (TRs) Q1, Q2, Q3 are turned on, but since a diode D3 is biased reverse, no compensating voltage is applied to a varactor diode D1 of an antenna tuning circuit 12 from a compensating circuit 16. When the receiving frequency is a value between the low and the medium frequency, the TRs Q1, Q2, Q3 are turned on, the diode D3 is biased forward, and the correcting voltage is applied to the varactor diode D1 of the antenna tuning circuit 12 from the compensating circuit 16. This correcting voltage is selected so as to make the tracking error zero at the frequency of 800kHz. |
