Circuit frequency following technique transponder resonant

摘要: A transponder system (10) includes an interrogation unit (12) that transmits a first frequency F1 representing binary zero, and second F2, one. These signals are transmitted from interrogator resonant circuit (22) within radio module (16). The also (14) receives transmit signal (51) the at (42). (42) is tuned to F2. control (44) detects change in by decrease voltage amplitude with repositions switch (48) connects disconnects capacitors match of new (51).