| 摘要 |
PURPOSE:To obtain a mixer or a modulator in which the ternary distortion and cross modulation distortion are improved remarkably by inputting an RF signal from a source of a single gate field effect transistor (TR) and inputting a local oscillation signal from the gate. CONSTITUTION:A filter 7 cutting-off a high frequency (especially RF) signal is inserted to the source 1, the source 1 is connected to an RF signal input terminal 4, the gate 2 is connected to a local oscillation (LO) signal input terminal 5 and the drain 3 is connected respectively to an IF signal output terminal 6 respectively. Then the RF signal inputted from the source is mixed or modulated with the LO signal inputted from the gate and the result is outputted to the drain 3. It is required to design the filter 7 that the resistance in terms of DC is suppressed to one ohm or lower and consists of such a device as an inductor or a 1/4 wavelength stub. Thus, the source resistance is decreased, low noise is attained and the RF signal is inputted to the source efficiently. In an MMIC mixer or an MMIC modulation circuit, the RF signal and the LO signal are inputted through a matching circuit 12 and the IF output is outputted through the matching circuit 12.
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