PURPOSE: To enable to detect the maximum point accurately with conventional microcomputer and to automate the adjustment of receiver, by temporarily storing the signal waveform swept in high speed to the variable delay circuit.

CONSTITUTION: The sweep signal is input to the receiver to be adjusted and high speed sweep is made, then the peak waveform a is obtained at coarse adjusting point, and the sweep waveform A is fed to the signal processing circuit 3. Further, the waveform B rejecting the noise component (c) is fed to the variable delay circuit 4, and the output of the circuit 4 transmitting data in high speed through the use of the clock C produced based on the waveform (a) is transmitted to CPU2 via the input and output circuit 7. Further, the circuit 7 selects the clock C in response to the operation speed of CPU2, resulting in being low speed data A/D conversion 6 and being fed to the CPU2. The previous data and the next data are sequentially compared to read in the maximum point of the sweep signal.