| 摘要 |
PURPOSE:To keep the conversion loss to a proper value independently of temperature by using a heat sensing resistive element to constitute a bias circuit. CONSTITUTION:The bias circuit setting a bias voltage to a mixer diode 2 is constituted by using the heat sensing element 1 in place of a constant resistor. Even when an input level of a local oscillation signal is lowered at high temperature, since the resistance value of the heat sensing resistive element 1 is changed smaller, a mixer current is kept nearly to a constant value. At a low temperature, even when the input level of the local oscillation signal is increased, since the resistance of the element 1 changes larger, the mixer current is kept nearly a constant value similarly. Thus, the temperature fluctuation of the conversion loss of the frequency conversion is minimized.
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