| 摘要 |
PURPOSE:To prevent a tracking error by controlling a voltage impressed from a control signal setting circuit to a high frequency amplifier so that an output of an intermediate frequency signal (IF) is maximized when an output of a reference signal transmitter is inputted to the high frequency amplifier. CONSTITUTION:An SW15 is connected to a reference signal generator 14, the same signal as a reception desired frequency is inputted and the signal is given to the high frequency amplifier 2, the result is mixed (4) with an output of a local oscillator 3 so as to generate an IF, which amplified (5). A frequency signal is extracted from the local oscillator 3, subjected to A/D conversion 6, a part of an output of the intermediate frequency amplifier 5 is extracted and subjected to A/D conversion 7 and both the results are inputted to a control signal setting circuit 9. A digital signal of a DC voltage is subjected to D/A conversion 8 and the results VT1, VT2... obtained by the control signal setting circuit 9 so as to maximize the output level of the IF are given sequentially to the 2nd, 3rd... tuning circuit elements from the 1st tuning circuit element of the high frequency amplifier circuit 2, a VTi is set and the SW15 is connected to an antenna 1. In changing the reception frequency, a command is given from an external command terminal 10. Thus, the tracking error is prevented. |
