Patent ID: 7786923
Filing Date: 2010-08-31
Classification: H03J

Abstract:
1. An interrogator that is incorporated in a communication system in which each of at least one transponder is operable, upon reception of a main carrier wave transmitted from said interrogator, to respond to said interrogator with a reflected wave that is generated by modulating the main carrier wave, said interrogator comprising: a transmitting portion operable to transmit the main carrier wave; a receiving portion operable to receive the reflected wave as a received signal; at least one first frequency-converter each operable to generate an intermediate frequency signal, by multiplying the received signal with a first local signal that is generated by a first local oscillator; at least one second frequency-converter each operable to generate a demodulated signal, by multiplying a converted signal converted from the intermediate frequency signal, with a second local signal that is generated by a second local oscillator; and a phase controller operable to control phase of the second local signal.