| 摘要 |
PROBLEM TO BE SOLVED: To improve error rate characteristics and to improve reception performance by reducing a group delay ripple deviation due to ceramic filter or the like. SOLUTION: A first ceramic filter 14 passes and filters a signal within a prescribed band among signals received from a second mixer 10. A phase shift circuit 16 shifts the phase of the signal which pass through the first ceramic filter 14 and sends the signal to a second ceramic filter 15. The first and second ceramic filters have almost the same group delay characteristics and are cascade-connected for providing a satisfactory single signal selection degree, by improving the attenuation quantity characteristics. Since the phase shift circuit 16 shifts the phase of the signal, frequency points for making adverse group delay ripple deviations in the first and second ceramic filters 14 and 15 can be set mutually different.
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