| 摘要 |
<p>PROBLEM TO BE SOLVED: To make a frequency of a return signal stable by synchronizing a frequency of a signal to be sent through a return path with a carrier signal frequency. SOLUTION: A high pass filter 16 filters a useful signal of a reference signal with 2.4GHz and provides an output to a 1st input of a mixer 14 in a return path. The mixer 14 that receives the filtered signal and a signal with 12.7GHz provides an output of a reference signal of 15.1GHz. The output signal is filtered by a low pass filter 15 and its output is used to transpose the useful signal of the CDMA system recovered at the 1st input of the mixer 17 and the filter 15 eliminates the reference signal of 2.4GHz. The mixer 17 filters an IF band signal from a reception path to eliminate an IF band signal. The signal modulated by a signal of 17.4GHz is filtered at an output of the mixer 17, amplified by a power amplifier 19 and transmitted from an antenna 5 via a diplexer 7. Thus, no synthesizer is required for a return signal frequency.</p> |
