Patent ID: 6617962
Filing Date: 2003-09-09
Classification: G06K

Abstract:
An interrogator for a radio identification system having a plurality of tags, selected one of said tags operating at a first frequency, and said other tags operating at a second frequency, said interrogator comprising:(a) a first radio frequency module having a transmitter for transmitting an output signal at said first frequency to said tags, and including a receiver for receiving return signals transmitted by said tags operating at said first frequency and modulated with a first protocol, and said receiver including means for dividing said return signals into multiple channels and means for converting said return signals into pulses; (b) a second radio frequency module having a transmitter for transmitting an output signal at said second frequency to said tags, and including a receiver for receiving return signals transmitted by said tags operating at said second frequency and modulated with a second protocol different from the first protocol, and said receiver including means for dividing said return signals into multiple channels and means for converting said return signals into pulses; (c) a controller module coupled to said first and second radio frequency modules, said controller module including means for controlling said transmitters for transmitting said output signals to said tags, and including decoder means for decoding said return signals received from said tags, said decoder means including synchronization means for synchronizing the frequency of said pulses and means for extracting information from said pulses according to the protocol associated with the tag transmitting the return signal, and said decoder means including code checking means for checking said pulses and means for selecting the channel without code violations.