| 摘要 |
PROBLEM TO BE SOLVED: To provide a 90°phase shifter capable of producing an output signal having a 90°phase difference with high precision by performing frequency dividing operation stably even when the output level of a phase comparator is excessively high. SOLUTION: The 90°phase shifter comprises a 1/2 frequency divider 30 producing two system signals having a phase difference of 90°from each other and a frequency equal to 1/2 that of an input signal, a phase comparator 40 for comparing the phase of output signals from the 1/2 frequency divider 30, and a limiter circuit 50 for limiting the output signal from the phase comparator 40 wherein the output signal from the limiter circuit 50 is fed back, as a DC offset, to the input end of the 1/2 frequency divider 30. COPYRIGHT: (C)2005,JPO&NCIPI
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