| 摘要 |
<p>The invention concerns methods for modulating the amplitude of a carrier designed in particular to interrogate an authentication label operating without contact. It consists in powering the output transistor (301) of the interrogation signal transmitter using a shock impedance (304) directly connected to a power source, and in controlling said transistor with a rectangular signal comprising pulses succeeding one another at the frequency of the carrier and width-modulated. Said method enables to reduce the transmitter power consumption, to reduce the battery pack voltage to a minimum and to reduce the number of components.</p> |
