| 摘要 |
<p>The present invention provides method and apparatus which enhance the probability of identification of a number of transmitters (1), typically transponders, which are all transmitting data to a receiver. The invention is applicable to a number of systems including passive radio-frequency transponders systems, systems in which a number of self-powered transmitters must be identified by a receiver, or systems in which a number of transmitters broadcast using a randomly delayed 'back-end and retry' algorithm. Each transmitter (1) is adapted to transmit at intervals and comprises means for generating transmissions, means for calculating the duration of the intervals between successive transmissions and means (20) for enabling the transmitter at random or pseudo-random intervals related to an operating frequency of local timing means (21). In passive RFID systems, the frequency of the local timing means is indeterminate, being unspecified until the transmitter is in operation.</p> |
