SYNTHESIZER RECEIVER

PURPOSE:To secure an optimum reception state all the time, by detecting wether an interference signal of frequency close to the frequency a desired station is present or not by using the IF output of a front end part, and switching signal pressing bands automatically at an IF amplification stage. CONSTITUTION:If there is an adjacent interference wave in addition to a desired signal to be received, and IF signal and a component originating from the adjacent disturbing wave appear at the output part of the front end part 2. Then, an interference wave level detector 9 compares an IF level based upon the interference wave with a preset level. An output based upon the comparison result is applied to an IF band contol part 10, which outputs a control signal for selecting an IF circuit having the best band width. Consequently, the output of the front end part 2 is amplified by the IF circuit.