Apparatus for comparing the amplitudes of modulation of two modulation signals of different frequency

Claim 2

APPARATUS FOR COMPARING THE AMPLITUDES OF TWO INPUT SIGNALS OF DIFFERENT FREQUENCIES COMPRISING A SIGNAL SOURCE PROVIDING A REFERENCE SIGNAL OF A FREQUENCY EXACTLY MIDWAY BETWEEN THAT OF THE TWO INPUT SIGNAL, MEANS FOR ADJUSTING THE PHASE OF THE REFERENCE SIGNAL, A BALANCED MODULATOR FOR AMPLITUDE-MODULATING THE PHASE-ADJUSTED MEAN FREQUENCY SIGNAL WITH THE COMBINED INPUT SIGNALS, A PHASE SENSITIVE DETECTOR FOR DETECTING THE AMPLITUDE OF THE OUTPUT SIGNAL FROM THE BALANCED MODULATOR AT A FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEN THE FREQUENCIES OF THE TWO INPUTS SIGNALS, MEANS FOR FEEDING TO SAID PHASE SENSITIVE DETECTOR A REFERENCE SIGNAL OF SAID FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEEN THE FREQUENCY OF THE TWO INPUT SIGNALS AND IN PHASE WITH THE COMPONENT OF THE DETECTOR INPUT REPRESENTATIVE OF THE DIFFERENCE OF AMPLITUDE OF SAID INPUT SIGNALS, A SIGNAL SOURCE PROVIDING A FURTHER SIGNAL OF A FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEN THE FREQUENCIES OF THE TWO INPUT SIGNALS INTO SAID DETECTOR, SAID FURTHER SIGNAL BEING IN PHASE WITH THE COMPONENT OF THE DETECTOR INPUT REPRESENTATIVE OF THE DIFFERENCE OF AMPLITUDE OF THE TWO INPUT SIGNALS, MEANS FOR ADJUSTING THE AMPLITUDE OF SAID FURTHER SIGNAL, AND MEANS FOR FEEDING THE ADJUSTED AMPLITUDE SIGNAL TO SAID PHASE SENSITIVE DETECTOR.

Claim 3

IN AN I.L.S. SYSTEM, APPARATUS FOR DETERMINING WHEREIN INPUT SIGNALS OF FREQUENCIES 90 C./S. AND 150 C./S., RECEIVED AS MODULATIONS ON CARRIERS OF THE SAME FREQUENCY, HAVE A PREDETERMINED DIFFERENCE OF AMPLITUDE COMPRISING MEANS RESPONSIVE TO THE RECEIVED SIGNALS PROVIDING A MEAN FREQUENCY REFERENCE SIGNAL OF A FREQUENCY EXACTLY MIDWAY BETWEEN THAT OF THE TWO INPUT SIGNALS, MEANS FOR ADJUSTING THE PHASE OF THE MEAN FREQUENCY REFERENCE SIGNAL, A BALANCED MODULATOR FOR AMPLITUDE-MODULATING THE PHASE-ADJUSTED MEAN FREQUENCY SIGNAL WITH THE COMBINED INPUT SIGNALS, A DETECTOR FOR DETECTING THE AMPLITUDE OF THE OUTPUT SIGNAL FROM THE BALANCED MODULATOR AT A FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEN THE FREQUENCIES OF THE TWO INPUT SIGNALS, A DIRECT VOLTAGE SOURCE, A FREQUENCY DIVIDER DIVIDING SAID MEAN FREQUENCY REFERENCE SIGNAL BY A FACTOR OF FOUR, A MODULATOR MODULATING SAID DIRECT VOLTAGE SOURCE WITH THE OUTPUT OF SAID DIVIDER WHICH IS IN PHASE WITH THE COMPONENT OF THE DETECTOR INPUT REPRESENTATIVE OF THE DIFFERENCE OF AMPLITUDE OF THE TWO INPUT SIGNALS, MEANS FOR ADJUSTING THE AMPLITUDE OF A SIGNAL FOR SAID MODULATOR TO PROVIDE AN OFFSETTING SIGNAL OF ADJUSTABLE AMPLITUDE AND OF A FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEN THE FREQUENCIES OF THE TWO INPUT SIGNALS AND MEANS FOR FEEDING SAID OFF-SETTING SIGNAL INTO SAID DETECTOR.

Claim 4

IN AN I.L.S. SYSTEM, APPARATUS FOR DETERMINING WHEREIN INPUT SIGNALS OF FREQUENCIES 90 C./S. AND 150 C./S., RECEIVED AS MODULATIONS ON CARRIERS OF THE SAME FREQUENCY, HAVE A PREDETERMINED DIFFERENCE OF AMPLITUDE COMPRISING MEANS RESPONSIVE TO THE RECEIVED SIGNALS PROVIDING A MEAN FREQUENCY REFERENCE SIGNAL OF A FREQUENCY EXACTLY MIDWAY BETWEEN THAT OF THE TWO INPUT SIGNALS, MEANS FOR ADJUSTING THE PHASE OF THE MEAN FREQUENCY REFERENCE SIGNAL, A BALANCED MODULATOR FOR AMPLITUDE-MODULATING THE PHASE-ADJUSTED MEAN FREQUENCY SIGNAL WITH THE COMBINED INPUT SIGNALS, A DETECTOR FOR DETECTING THE AMPLITUDE OF THE OUTPUT SIGNAL FROM THE BALANCED MODULATOR AT A FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEN THE FREQUENCIES OF THE TWO INPUT SIGNALS, A DIRECT VOLTAGE SOURCE, A FREQUENCY DIVIDER DIVIDING SAID MEAN FREQUENCY REFERENCE SIGNAL BY A FACTOR OF FOUR, A MODULATOR MODULATING SAID DIRECT VOLTAGE SOURCE WITH THE OUTPUT OF SAID DIVIDER WHICH IS IN PHASE WITH THE COMPONENT OF THE DETECTOR INPUT REPRESENTATIVE OF THE DIFFERENCE OF AMPLITUDE OF THE TWO INPUT SIGNALS, MEANS FOR ADJUSTING THE AMPLITUDE OF A SIGNAL FOR SAID MODULATOR TO PROVIDE AN OFFSETTING SIGNAL OF ADJUSTABLE AMPLITUDE AND OF A FREQUENCY EQUAL TO HALF THE DIFFERENCE BETWEEN THE FREQUENCIES OF THE TWO INPUT SIGNALS AND MEANS FOR FEEDING SAID OFF-SETTING SIGNAL INTO SAID DETECTOR.