SPURIOUS DETECTION CIRCUIT AND RADIO EQUIPMENT PROVIDED WITH THE CIRCUIT

PROBLEM TO BE SOLVED: To easily detect the presence of spurious radiation wave leaked to a main signal circuit with respect to the spurious detection circuit and the radio equipment provided with the spurious detection circuit. SOLUTION: A branch signal (3) (f1 , sp) of a main signal (1) and a local signal (8) (fi ) with the same frequency as that of the main signal (1) are mixed by a mixer 13 and a frequency component (fi -fi , fi -sp) lower than the frequency of the main signal (1) from an output (f1 i , fi ±sp) of the mixer is extracted and an AC signal component (sp-fi ) in the extracted signal is detected and then the presence of a spurious radiation sp leaked to the main signal fi is detected.