FM RECEPTION EQUIPMENT

PROBLEM TO BE SOLVED: To improve S/N of a detection output without being affected by the intensity of a reception radio wave by changing the inclination of the S curve of the detection output in accordance with the intensity of the reception radio wave. SOLUTION: The reference voltage of a comparator 7 is pre-liminarily set so that the output of the comparator 7 goes to the row level at the time when the FM signal inputted to an up amplifier 1 is made weaker than a point (point A) where the noise level exceeds the signal level for strong input. When the level of the FM signal is made lower than the point A because of the weak reception radio wave, the output of the comparator 7 goes to the low level, a switching transistor TR Q1 is turned off. Then, the resistance value of the whole of an oscillator 3 for detection is made larger than that for turning-on of the TR Q1 though the oscillation frequency of this oscillator is not changed, and the voltage level of the oscillation output is raised in accordance with this increase. As the result, the inclination of the S curve showing the detection output characteristic is changed to narrow the width of the dynamic range of detection output.