CPC H04B 5/0031 (2013.01) [H04B 5/0037 (2013.01); H04B 5/0062 (2013.01); H04B 5/0093 (2013.01)] | 20 Claims |
1. A contactless integrated circuit (IC) card reader configured to communicate with a contactless IC card, comprising:
an antenna circuit;
a transmission circuit configured to generate a carrier signal;
a variable amplifier configured to amplify the carrier signal at an amplification gain and to output the amplified carrier signal to the antenna circuit as a transmission signal;
a variable attenuator configured to attenuate a receive signal received through the antenna circuit at an attenuation ratio;
a reception circuit configured to filter the carrier signal from the attenuated receive signal and to generate a filtered receive signal; and
a controller configured to compare an amplitude of the filtered receive signal with a reference level, and to control both the amplification gain of the variable amplifier and the attenuation ratio of the variable attenuator based on a result of the comparison.
|