Abstract: An electronic identification system includes common transceiver and signal processing apparatus, and relative small electronic circuitry, referred to as a "tag", secured to each item of a population to be identified. Each tag is assigned a multi-bit digital code which may or may not be unique.The common equipment determines whether any desired tag-bearing item is nearby by emitting a phase modulated radio frequency wave embodying the requisite tag code, and examining the output of a homodyne mixer, operating on a radar-like recovered reflection signal, for a predetermined signatory response. Such a response will be generated only by a tag circuit responding to a match between its stored encoding and that of the interrogation signal by changing the effective cross sectional reflecting area of the tag antenna.