Method for determining the running digital sum of a serial data signal

摘要

The invention relates to a method for determining and monitoring the running digital sum (LDS) which is formed from the bits of a coded data stream and is used for detecting transmission errors, the data bits of the binary digit 1 being weighted with the value +1 and those with the binary digit 0 being weighted with the value -1 and the transgression of a particular predeterminable amount by the LDS leading to a limiting of the LDS to this predeterminable amount and to an error indication, and is characterised by the fact that the serial data stream is divided into n parallel part-data streams of the same speed, that in each case one bit of these n part-data streams is temporarily stored in an n-bit memory and that the pattern of these n bits is detected and, on the basis of a comparison between this bit pattern and the last LDS value, the new LDS is determined on the basis of a state diagram previously determined. The division into n part-data streams results in a reduction in the processing speed for determining the LDS to 1/n of the transmission speed. <IMAGE>