| 摘要 |
PURPOSE:To simplify the circuit of the frequency converting unit having a transmission double frequency converter and a receiving double frequency converter, by using the second-stage local signal generator commonly for respective frequency converters. CONSTITUTION:The second-stage local signal generator 15 is connected to the second-stage mixer 5 of transmission double frequency converter 7 as well as the second-stage mixer 13 of receiving double frequency converter 14 and is used commonly for them. Frequencies of the second IF signals (d) and (e) of respective mixers above are set to the half of the difference between frequencies assigned to transmission and receiving. Further, mixer 5 obtains the sum of the frequency of the second IF signal (e) and the frequency of local signal (f) of local signal generator 15, and mixer 13 obtains the difference between the frequency of the third IF signal and the frequency of local signal (f), so that generator 15 can be used commonly. Thus, the whole of the unit can be amplified by using the second-stage local signal generator commonly. |
