| 摘要 |
PURPOSE:To reduce interference between adjacent channels by providing a path length adjustment circuit and a phase shift control device for each system between a branching filter and a synthesizer in the heterodyne repeater. CONSTITUTION:An RF signal (a) inputted from a microwave transmission line 9 is branched into two at a branching filter 10 and they are converted into IF signals by frequency converters 11, 12 respectively. Then the one is inputted directly to frequency converters 13, 14 via a path length adjustment circuit 25 and inversely converted into an RF signal. The part of the signals is given to narrow band filters 32, 33, from which a carrier component of an adjacent channel is extracted, compared with a phase comparator 34, an endless phase shifter 29 is controlled by the accumulate count of the output so that the phase of an adjacent channel in duplicate between systems is matched. Thus, no interference is caused even when signals of both the systems are synthesized by a synthesizer 15 by arranging a phase of a local oscillation signal for frequency conversion and an electric path length basically and making the phases of the signal component in duplicate between both the systems coincident. |
