Patent ID: 8391318

Claim:
A communication system, comprising: a data bus; multiple user nodes connected to the data bus, data transmission taking place via the data bus in data frames, wherein each data frame including at least one of at least one data field, at least one control field and at least one check sum field, at least one of the users having a high-precision clock generator and the remaining users having a lower precision clock generator, wherein the lower precision clock generator is less precise than the high-precision clock generator, and during operation calibration messages being present on the data bus, and at least one of the users, which has the lower precision clock generator, receiving a calibration message; and a calibration control system for calibrating the lower precision clock generator to a system clock signal of the data bus, taking into account information contained in the received calibration message, wherein a number of system clock signals contained in a bit time may be configured, and wherein the calibration control system is for measuring in oscillator periods a distance between a first edge of an oscillator period in the data field or in the control field of a received data frame and another edge of the oscillator period in a field of the received data frame, counting the number of bits between the two edges, and setting a clock divider, which generates a system clock signal of a data bus protocol control system of the at least one user having the lower precision clock generator, so that a system clock signal period has a length of oscillator periods equal to the distance between a first edge of the oscillator period in the data field or in the control field of a received data frame and another edge of the oscillator period in a field of the received data frame divided by the product of the number of bits between the two edges and the number of system clock signals contained in a bit time.