| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To normally wireless-transmit a signal even if a driving electric power varies in accordance with change of a distance from an external device. <P>SOLUTION: A communication apparatus 1 is driven based on reception of supply of electric power through an antenna 20 from an external reader/writer. An intensity detecting section 11 detects an intensity of received waves received through the antenna 20. A transmission signal generation section 12 generates a transmission signal pulse obtained by superimposing transmission data to be transmitted to the reader/writer with a reference pulse. A modulation section 13 performs load modulation according to the transmission signal pulse outputted from the transmission signal generation section 12. Thereby, a wireless signal according to the transmission data is transmitted to the reader/writer. A pulse control section 14 changes a duty ratio of the reference pulse appearing in the transmission signal pulse so that a period of its H-level is more shortened as the intensity of the received waves is lower, to control a form of a modulation signal waveform after the load modulation. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
