| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for preventing the group delay characteristic and frequency characteristic particularly included in a canceler from posing a problem in obtaining a suppression amount over a wide band, while the canceller with a suppression amount of approximately 20 dB is required because the performance of the out-of-band signal suppression amount of a tunable filter is approximately 30 dB and is small as compared to a suppression amount of 50 dB of an ordinary general duplexer. <P>SOLUTION: A delay element equivalent to the group delay of an amplifier is disposed in a signal path of a tunable filter. A canceler contains a matching circuit for adjusting amplitude, phase and delay, a wide band amplifier with few amplitude fluctuations and phase fluctuations over frequency bands from a transmission signal to a reception signal, a variable impedance transmission side coupler and a variable impedance reception side coupler. <P>COPYRIGHT: (C)2012,JPO&INPIT |
