Methods and apparatuses for identification of the position of data packets which are located in a serial received data stream

Apparatus for identification of the position of data packets (P1, P2, . . . ) which are located in a serial received data stream and in each case have check data in a check field and a check sum (CRC) which is formed using the check data, characterized by

• a comparison unit (9) through which the received data stream is passed in serial form and which forms a new check sum (CRC′) with each received symbol to be newly added and compares this new check sum with data which are looked at for the associated received check sum (CRC), the comparison unit determining the position of the data packet in the serial data stream from the comparison of the new check sum (CRC′) and the associated received check sum (CRC);
• a delay unit (10) which likewise receives the received data stream in serial form and whose length (n) corresponds to the number of bits of check data and in the check sum (CRC);
• and
• a feedback state (11), which is located between the output of the delay unit (10) and further inputs of the comparison unit (9), for forming values in order to eliminate the influence on the comparison of all data which do not belong to the check data and the check sum (CRC).

Apparatus for identification of the position of data packets (P1, P2, . . . ) which are located in a serial received data stream and in each case have check data in a check field and a check sum (CRC) which is formed using the check data, characterized by

• a number of parallel-connected comparison units (221, 222, . . . , 22n) which corresponds to the number of bits of check data and in the check sum (CRC), through which comparison units the received data steam is passed in serial form and which form a new check sum (CRC′) with each received signal to be newly added and compare this new check sum with data which are looked at for the associated received check sum (CRC), the comparison units determining the position of the data packet in the serial data stream from the comparison of the new check sum (CRC′) and the associated received check sum (CRC);;
• a delay unit (21) which likewise receives the received data stream in serial form and whose length (n) corresponds to the number of bits of check data and in the check sum (CRC);
• and
• a logic gate (24), which is connected tot he output of all the comparison units, for supplying a signal (Found CRC) when the comparison is found to be positive in one of the comparison units.

Method for identification of the position of data packets (P1, P2, . . . ) in a serial data stream and each data packet having a unique position in the serial data stream, check data in a check field and a check sum (CRC) which is formed using the check data, said method comprising:

• passing the received data stream in serial form through a comparison unit (9), the received data stream is at the same time also passed in serial form through a delay unit (10) whose length (n) corresponds to the number of bits of check data and check sum, and in that the output signal of the delay unit (10), weighted by values (ai), is used to influence the comparison which is carried out in the comparison unit (9) and the comparison unit (9) which forms a new check sum (CRC′) with each received signal to be newly added and compares this new check sum (CRC′) with data which are regarded as the associated received check sum (CRC);
• determining the position of the data packet in the serial data stream from the comparison of the new check sum (CRC′) and the associated received check sum (CRC);
• and
• eliminating, during the comparison, the influence of all data which are not associated with the check data and the check sum (CRC).