| 摘要 |
PURPOSE:To compensate exactly a temperature irrespestive of whether a temperature characteristic of a circuit to be compensated is linear or nonlinear, by compensating a temperature by applying an analog signal to the circuit to be compensated, as a control signal. CONSTITUTION:A temperature voltage converting circuit 3 detects a forward voltage drop of a diode by supplying a constant current to a temperature sensor 1, amplifies it and generates an output voltage. Also, an ROM5 outputs a signal of a digital value of a necessary control voltage corresponding to a temperature, when a digital signal of an A/D converter 4 is applied as an address. A D/A converter 6 D/A-converts this digital signal, and outputs it as a DC signal. In this regard, its value is determined and written in the ROM5 so as to become an attenuation quantity for compensating a temperature characteristic of the gain of an amplifier to be compensated 12, in accordance with an ambient temperature of a circuit to be controller 2. Accordingly, a variation based on the temperature characteristic of the gain of the amplifier to be compensated 12 is offset by a variation due to temperature of an attenuation quantity of a variable attenuator 11, and the gain of the circuit to be compensated 2 becomes constant irrespective of the ambient temperature.
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