High sensitivity reader for passive transponders

The present invention receives the first signal Tx from reading equipment, and relates to the reading equipment (10) which identifies the passive transponder (12) which has an antenna which transmits the second signal Rx to this reading equipment. The time base machine (54) with which the reading equipment of the present invention generates: sine wave signal; with the antenna of the control circuit (64) ; above-mentioned transponder. Modulator (56) ; demodulator (58) ; decoder (60) which transmits the data which modulates a sine wave signal so that the signal which transmits the command which will form the first signal (Tx) of the above if received may be generated to the above-mentioned control circuit (64) ; it has communications interface (62) ; and an antenna (14). The above-mentioned demodulator (60) connected to the antenna (14) which receives the second signal (Rx) of the above has the adding machine (70) designed as the data by which it is generated in two multipliers (76, 78) which are inverter types, and the above-mentioned multipliers (76, 78) combined in one (78) of them. [Selection figure] Fig. 5