| 摘要 |
<p>PURPOSE:To compensate oscillating frequency fluctuation attended with temperature change by providing a transient temperature correction circuit generating a temperature correction signal representing the same characteristic as the temperature characteristic in the inside of an IC when temperature is fluctuated with on/off of power to a voltage controlled oscillator circuit as a temperature compensation circuit. CONSTITUTION:When a power Vcc is applied and the internal temperature of the IC rises along a curve K0 at a point of time t0, a voltage of a capacitor C21 rises with a charging current flowing to a resistor R21 of a transient temperature correction circuit 25 with the same time constant and the capacitance of varactor diode D31 of an adjusting signal generating circuit D26 is controlled in a direction cancelling the change in the curve K0 so as to compensate the change in the oscillating frequency of a VCO11. When the power Vcc is cut off at a point of time tOFF from the steady state, the charging voltage of the capacitor C21 is discharged with the similar change as a curve K1, and the capacitance of the diode D31 compensates the change in the oscillating frequency of the VCO11. The circuit 25 is operated similarly even when the power is cut off before the steady state is not attained after the power supply ON at points of times t01, t02, t10. Caption 22 is a steady-state temperature correction circuit.</p> |
