FREQUENCY CONVERSION TYPE RADIO RELAY AMPLIFIER SYSTEM

摘要

PROBLEM TO BE SOLVED: To allow the system to employ an inexpensive reference oscillator by using the reference oscillator in common for local oscillation signals for input/output IF conversion and reconversion so as to eliminate a frequency deviation in input and output high frequency signals thereby enhancing a frequency deviation in the high frequency signals to a degree of depending only a base station and a mobile station and reducing the frequency deviation by two orders of magnitude or more in terms of stability. SOLUTION: A reference oscillator 60 is used in common for an input side PLL circuit 59 and an output side PLL circuit 63. Suppose that a frequency of the reference oscillator 60 is deviated positively under a frequency deviation FL1±Δf of an input side local oscillation signal, the frequency of the signal is fL+Δf and an output side frequency is deviated positively and the signal frequency is fL2 +Δf2 . SinceΔf1 =Δf2 , a frequency deviation as a difference between the input and output frequencies is cancelled out in the respective deviations, resulting that the frequency deviation is independently of the effect of the frequency deviation of the local oscillator. The frequency deviation above relates to an in-band characteristic deterioration or the like resulting from a deviation of an intermediate frequency from its center frequency, but this is substantially negligibly small.