Electrical surface toni control unit for a variable data transmission with pulse width modulation

摘要

It is an electronic key access system for vehicles which, in a safety - ecu (11), which is mounted in a vehicle, in order to provide an electronic key (23) via a radio communication with the same to check. The ecu (11) contains a cpu (13) and a pwm - output unit (14). The pwm - output unit (14) produces a under refraction request to each edgeinstant of the pwm - pulse, the relative to the electronic key (23) is sent. The cpu (13) is a pattern of the pwm - output variable of a next cycle in response to a lower refraction request, so that the pwm - output unit (14) a pulse corresponding to the set transmits pwm - output patterns or sends. The cpu (13) also keeps the pulse transmission to, if no response from the electronic key (23) in the course of the communication in a plurality of stages is received.