| 摘要 |
<p>A data transmission device using electromagnetic wave radiation in a contactless transceiver system toward a contactless object, the data bits transmitted corresponding to the half cycle of an initial time interval during which electromagnetic waves are emitted at a predetermined carrier frequency and to a second splitting time interval during which there is a split in transmission of the electromagnetic waves at the predetermined carrier frequency. During said second splitting time interval, generation means ( 40, 42, 44, 46, 48 ) generate electromagnetic waves having a frequency which is double the predetermined carrier frequency resulting in an attenuation of the radiated field by the antenna greater than a predetermined value such as 30 dB.</p> |
