| 摘要 |
PURPOSE:To eliminate an interference of a multiple wave outputted from a shift oscillator by setting a level of a high frequency input signal to above a level of an output signal of the shift oscillator. CONSTITUTION:The figure shows a relation between a receiving wave input level Pr to a mixer 2 and a level Pn of an (n) multiple wave outputted from the mixer 2 by using an output Ps of a shift oscillator 3 as a parameter. According to a prescription of CCIR, 1PW is allowed to an interference noise, and when it is expressed in terms of a level, it becomes 90dB. In the figure, when the level Pr exceeds the level Ps, as for a difference between the levels Pr, Pn, 100dB or more can be taken, and a transmitting wave level Pt is a value obtained by subtracting a conversion loss of the mixer 2, for instance, 10dB from the level Pr, but a difference between the levels Pt, Pn becomes 90dB or more, and an interference by the (n) multiple wave can be reduced to a negligible degree. |
