Terminal for generation of electromagnetic field interacting with transponder when it enters into this field has phase comparator, transformer circuit and capacitive element for regulation of phase of signal in oscillating circuit

摘要

An oscillating circuit (R1,L1,24) receives an AC HF voltage. A device is provided to determine a distance between the transponder of the terminal without emission towards the terminal. A phase comparator (21), a transformer circuit (23) and a capacitive element (24) are used for regulation of the phase of the signal in the oscillating circuit in relation to a reference signal.