Swept frequency circuit testing system

Claim 1

APPARATUS FOR MEASURING THE POWER GAIN OR LOSS AS A FUNCTION OF FREQUENCY OF A NETWORK HAVING AN INPUT AND AN OUTPUT, COMPRISING AN OSCILLATOR; MEANS FOR SWEEPING THE FREQUENCY OF THE OSCILLATOR THROUGH FIXED BAND REPEATEDLY AT A LOW REPETITION RATE, THE OUTPUT OF THE OSCILLATOR BEING COUPLED TO THE INPUT OF THE NETWORK; A CATHODE RAY SCOPE INCLUDING FIRST AND SECOND BEAM-DEFLECTION MEANS; MEANS RESPONSIVE TO THE FREQUENCY SWEEPING MEANS FOR ACTUATING THE FIRST BEAM-DEFLECTION MEANS TO DEFLECT THE CATHODE RAY BEAM IN PROPORTION TO THE FREQUENCY OF THE OSCILLATOR OUTPUT; MEANS FOR ACTUATING THE SECOND BEAM-DEFLECTION MEANS TO DEFLECT THE CATHODE RAY BEAM AT PREDETERMINED FREQUENCIES OF THE OSCILLATOR OUTPUT TO PROVIDE A FREQUENCY REFERENCE ON THE SCOPE; REFERENCE CHANNEL MEANS INCLUDING AN AMPLITUDE DETECTOR AND LOW PASS FILTER, THE OUTPUT OF THE OSCILLATOR BEING COUPLED TO THE INPUT OF THE REFERENCE CHANNEL MEANS; COMPARISON CHANNEL MEANS INCLUDING A CALIBRATED ATTENUATOR, AMPLIFIER, AMPLITUDE DETECTOR, AND LOW PASS FILTER; MEANS FOR SELECTIVELY COUPLING THE OUTPUT OF THE OSCILLATOR AND THE OUTPUT OF THE NETWORK TO THE INPUT OF THE COMPARISON CHANNEL MEANS; SWITCHING MEANS FOR ALTERNATELY CONNECTING THE OUTPUT OF THE REFERNCE CHANNEL MEANS AND THE COMPARISON CHANNEL MEANS DIRECTLY TO THE SECOND BEAM-DEFLECTION MEANS, THE LOW PASS FILTERS, THE SWITCHING MEANS, AND THE SECOND BEAM DEFLECTION MEANS BEING DIRECT-COUPLED TO RESPOND TO THE D.-C. COMPONENT OF THE DETECTOR OUTPUTS; AND MEANS FOR DRIVING THE SWITCHING MEANS AT A FREQUENCY WHICH IS SUBSTANTIALLY HIGHER THAN THE SWEEP REPETITION RATE.