| 摘要 |
PROBLEM TO BE SOLVED: To reduce the semiconductor chip size of a 90-degree phase shifter for converting input signals into first and second differential signals to shift each signal phase by +45 degrees and by -45 degrees, respectively, thus outputting the phase-shifted signals and also to reduce the consumption current of the phase shifter. SOLUTION: The first and second differential signals are output from a differential amplifier 1. Signals 101 of one side of the first differential signals and signals 102 of the other side of the first differential signals are shifted in phase by +45 degrees and are output from the phase shifter 5 and from the phase shifter 8, respectively. Each of the signals is input to a differential amplifier 17. Signals 103 of one side of the second differential signals and signals 104 of the other side of the second differential signals are shifted in phase by -45 degrees, and output from the phase shifter 11 and from the phase shifter 14, respectively; and each of the signals is input to a differential amplifier 18. DC biases for signals 105, 106 of the first differential signals output from the phase shifters 5, 8 are set in a DC bias circuit 2, while the DC biases of signals 107, 108 of the second differential signals output from the phase shifters 11, 14 are set to the input potential with respect to the phase shifters 11, 14 by resisters 12, 15. COPYRIGHT: (C)2005,JPO&NCIPI
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