Spectrum analyzer

Claim 1

A FREQUENCY SPECTRUM ANALYZER COMPRISING: AN INPUT MIXER CIRCUIT CONNECTED TO RECEIVE AN INPUT SIGNAL; A VARIABLE FREQUENCY SIGNAL SOURCE CONNECTED TO SAID INPUT MIXER CIRCUIT AND ADAPTED TO GENERATE A SELECTIVELY VARIABLE FREQUENCY FOR PRODUCING DIFFERENCE FREQUENCY OUTPUT SIGNALS FROM SAID INPUT MIXER HAVING A DESIRED FUNDAMENTAL FREQUENCY AND HARMONICS THEREOF WITHIN A DETERMINABLE BANDWIDTH; A SECOND MIXER CIRCUIT CONNECTED TO RECEIVE SAID FUNDAMENTAL FREQUENCY AND HARMONIC SIGNALS; A SWEEP VOLTAGE GENERATOR CONNECTED TO RECEIVE A TIMING SIGNAL FOR GENERATING A TRIGGER SIGNAL OF VARYING AMPLITUDE; A SWEEP FREQENCY OSCILLATOR CONNECTED TO SAID SECOND MIXER AND OPERATIVELY RESPONSIVE TO SAID TRIGGER SIGNAL FOR GENERATING A REPETITIVE OUTPUT VARYING IN FREQUENCY SUBSTANTIALLY AS THE FREQUENCY VARIATION BETWEEN THE LIMITS OF SAID DETERMINED BANDWITH FOR PRODUCING OUTPUTS FROM SAID SECOND MIXER OF SUBSTANTIALLY ONE DETERMINABLE FREQUENCY AND DISPLACED IN TIME IN ACCORDANCE WITH RESPECTIVE FREQUENCY DISPLACEMENT AND SAID HARMONICS RELATIVE TO SAID FUNDAMENTAL FREQUENCY; AN ATTENUATING MEANS;