| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-frequency level adjusting circuit which is low cost and free of the effects of attenuation amount on the distortion characteristics without having to use a special component for high frequency, but a switching diode which is a general component for RF multiplex transmission equipment. SOLUTION: The high-frequency level adjusting circuit includes: a first level adjustment unit which variably adjusts RF signal from a bias circuit of a first switching diode and outputs it to an output terminal; a second level adjustment unit which variably adjusts an RF signal from a bias circuit of a second switching diode and disposed in aπ-type attenuator; a bias circuit of a third switching diode outputting the RF signal from the second level adjustment unit to the output terminal; and a switching unit which switches the bias circuits of the first to third switching diodes. Then the paths for high-frequency adjustment of the RF signal are switched so as to secure attenuation amount until combining the characteristics of signal paths. COPYRIGHT: (C)2009,JPO&INPIT
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