| 摘要 |
A method of producing a closed synchronization loop for two-way communication between a transponder and an interrogator where different frequencies may be used for communication between interrogator and transponder. The invention is characterized in that communication between interrogator (1) and transponder (2) is accomplished by sending a clock signal from the interrogator to the transponder and vice versa, for controlling two-way communication between interrogator and transponder; in that the demodulation of data is effected at a low frequency, both when communication between interrogator (1) and transponder (2) is effected via microwave frequencies and via lower frequencies, by transmitting two or more microwave frequencies from the interrogator in that case when microwave frequencies are used, wherein a difference frequency constitutes a clock signal of the same frequency as the frequency of the clock signal when said communication is effected at lower frequencies. |
