Low-cost software-defined rfid interrogator with active transmit leakage cancellation

A RFID interrogator transceiver comprising:

• an antenna;
• a transmitting element operatively coupled to the antenna;
• a digital processor operatively coupled to the transmitting element, the digital processor comprising a transmit baseband waveform generator, the transmit baseband waveform generator comprising:
• a toggle element operatively coupled to the transmitting element;
• a countdown timer operatively coupled to the toggle element;
• a symbol-to-count translating element operatively coupled to the countdown timer;
• a symbol multiplexer operatively coupled to the symbol-to-count translating element;
• a random access memory organized to contain an arrangement of opcodes operatively coupled to the symbol multiplexer;
• an address counter operatively coupled to the random access memory;
• and
• a finite state machine operatively coupled to the address counter, the random access memory, and the symbol multiplexer, the finite state machine configured to increment the address counter and to interpret opcodes from the random access memory.

A RFID interrogator transceiver comprising:

• an antenna;
• a receiving element operatively coupled to the antenna;
• a digital processor operatively coupled to the receiving element, the digital processor comprising a channel bandpass filter, the channel bandpass filter comprising:
• a first second-order infinite-impulse-response digital resonator filter operatively coupled to the receiving element and configured at a first resonant frequency;
• and
• a second second-order infinite-impulse-response digital resonator filter operatively coupled to the first second-order infinite-impulse-response digital resonator filter and configured at a second resonant frequency.