| 摘要 |
PURPOSE:To provide the intermediate frequency circuit part which can evade deterioration of a bit error caused by a drift, even when a band pass filter for inputting an output signal of a frequency mixer and outputting only an intermediate frequency signal is that which drifts a passing frequency band due to its temperature variation. CONSTITUTION:A temperature sensor 10 for detecting a temperature of a band pass filter (ceramic filter) is provided, and also, a relation of a temperature of the above-mentioned ceramic filter and a passing frequency band is stored in advance in a ROM 5e, and by varying a value of a frequency division ratio N of a programmable frequency divider 15a in accordance with a detected temperature of the temperature sensor 10, a frequency of a signal f2 sent to a mixer from a PLL frequency synthesizer 3h is controlled so that the frequency of the output signal from the mixer becomes a center frequency of the frequency band of the temperature sensor 10. |
