Transponder decoder

Claim 1

DECODING APPARATUS THAT IS RESPONSIVE TO EITHER A TWO-PULSE INTERROGATION OR A THREE-PULSE INTERROGATION, SAID TWO-PULSE INTERROGATION COMPRISING A PAIR OF PULSES HAVING A PREDETERMINED TIME SPACING, EACH OF SAID PULSES OF THE PAIR BEING AN INTERROGATION PULSE AND ONE OF SAID PULSES OF THE PAIR ALSO BEING A SLIDELOBE SUPPRESSION PULSE, SAID THREE-PULSE INTERROGATION COMPRISING THREE PULSES P1, P2 AND P3 HAVING A PREDETERMINED TIME SPACING AND HAVING A PREDETERMINED AMPLITUDE RELATION, THE PULSE P1 AND P3 BEING INTERROGATION PULSES HAVING THE SAME TIME SPACING AS THE PAIR OF PULSES OF THE TWO-PULSE INTERROGATION, THE PULSE P2 BEING A SIDELOBE SUPPRESSION PULSE THAT IS SPACED CLOSE TO PULSE P1, SAID DECODING APPARATUS COMPRISING A PAIR OF PARALLEL CHANNELS, MEANS FOR APPLYING RECEIVED INTERROGATION PULSES TO SAID CHANNELS, ONE OF SAID CHANNELS INCLUDING AN AMPLITUDE COMPARISON MEANS FOR PREVENTING THE SECOND OCCURRING ONE OF THE PULSES P1 AND P2 FROM BEING PASSED IF ITS AMPLITUDE IS LESS THAN THAT OF THE FIRST OCCURRING OF THE PULSES P1 AND P2 BY A PREDETERMINED AMOUNT AND WHEREBY THE OUTPUT PULSES OF SAID ONE CHANNEL ARE DISTORTED WITH RESPECT TO THEIR ORIGINAL RELATIVE AMPLITUDES, THE SECOND OF SAID CHANNELS BEING NON-DISTORTING WITH RESPECT TO THE RELATIVE AMPLITUDES OF SAID PULSES; AN AMPLITUDE COMPARISON CIRCUIT TO WHICH THE OUTPUT PULSES OF SAID SECOND CHANNEL ARE APPLIED, SAID AMPLITUDE COMPARISON CIRCUIT COMPRISING MEANS FOR COMPARING THE AMPLITUDES OF SAID INTERROGATION PULSES FOR PRODUCING AN OUTPUT PULSE WHEN SAID INTERROGATION PULSES FOR PROHAVE A PREDETERMINED AMPLITUDE RELATION, MEANS FOR PRODUCING A COINCIDENCE OUTPUT PULSE IN RESPONSE TO THE INTERROGATION PULSES OF AN INTERROGATION HAVING A PREDETERMINED TIME SPACING, SAID DECODING APPARATUS HAVING AN OUTPUT LEAD, AND MEANS FOR SUPPLYING THE OUTPUT OF SAID AMPLITUDE COMPARISON CIRCUIT TO SAID OUTPUT LEAD IN RESPONSE TO THE OCCURRENCE OF SAID COINCIDENCE OUTPUT PULSE.