| 摘要 |
PURPOSE:To realize an inexpensive, stable circuit for a receiver and to make said circuit applicable to a mobile radio equipment and an automobile telephone loaded on a vehicle by putting together temperature compensation signal generation parts, using the lst and 2nd oscillators as said signal generation part and transmitting a feedback signal to an oscillation part. CONSTITUTION:The cut angles of crystal resonator used in the 1st local oscillation part 1(frequency division ratio in PLL:N2) and in the 2nd local oscillation part 2 are made almost the same, and their temperature characteristics are approximately coincided with each other. The 1st and 2nd local oscillation parts used here are variable frequency oscillators(VCXO), and frequqency changing amounts with respect to the voltages of the two local oscillation parts are almost the same. Thus the compensation signal can be easily controlled. Consequently, before the output of the temperature compensation signal generation part 5 is added to the feedback signal, a coefficient multiplying part to multiply the feedback signal by the coefficient is connected, and the frequency division feedback signal is set to N2/N1(N1:frequency division ratio to divide the frequency of the output of a reference outgoing part). Thus only one temperature compensation part is enough, whereby the overall receiver becomes a stable system.
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