Error monitoring in digital transmission systems

Claim 2

Apparatus for formatting a time division multiplexed signal including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (310) responsive to bits in a block of bits of the time division multiplexed signal (XTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions; and means (301, 304-306) for inserting said code word bits in predetermined ones of the additional bit positions of a subsequent block of bits of the time division multiplexed signal being transmitted to monitor errors in transmission.

Claim 3

Apparatus .Iadd.including means .Iaddend.for monitoring a received time division multiplexed signal including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (702) responsive to all the bits of a block of bits of the received time division multiplexed signal (RTDM) for generating .Iadd.in .Iaddend.accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additionsal bit position; and means (703) for comparing said code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate error indications.

Claim 4

Apparatus .Iadd.including means .Iaddend.for monitoring a received time division multiplexed signal including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (702) responsive to all the bits of a block of bits of the received time division multiplexed signal (RTDM) for generating .Iadd.in .Iaddend.accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additionsal bit position; and means (703) for comparing said code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate error indications.

Claim 5

Apparatus for transmitting and receiving time division multiplexed signals including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (300) for formatting the time division multiplexed signal (XTDM) including means (310) responsive to bits in a block of bits of the time division multiplexed signal (XTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, and means (301, 304-306) for inserting said code word bits in predetermined ones of the additional bit positions of a subsequent block of bits of the time division multiplexed signal being transmitted to monitor errors in transmission; and means (700) for monitoring a received time division multiplexed signal including means (702) responsive to bits of a block of bits of the received time division multiplexed signal (RTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, and means (703) for comparing said code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate error indications.

Claim 6

Apparatus for transmitting and receiving time division multiplexed signals including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (300) for formatting the time division multiplexed signal (XTDM) including means (310) responsive to bits in a block of bits of the time division multiplexed signal (XTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, and means (301, 304-306) for inserting said code word bits in predetermined ones of the additional bit positions of a subsequent block of bits of the time division multiplexed signal being transmitted to monitor errors in transmission; and means (700) for monitoring a received time division multiplexed signal including means (702) responsive to bits of a block of bits of the received time division multiplexed signal (RTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, and means (703) for comparing said code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate error indications.

Claim 7

Apparatus as defined in claims 1 or 2, wherein said code word generating means (310; 702) includes means (501) for generating said code word bits (CRC BITS) from a block having a predetermined number of bits of the time division multiplexed signal (XTDM; RTDM) and means for serially supplying said code word bits (502) during a next subsequent block of bits of the time division multiplexed signal.

Claim 8

Apparatus as defined in claim 1 or 2, wherein said prescribed criterion includes a predetermined cyclic code generator polynomial.

Claim 9

Apparatus as defined in claim 5 wherein said predetermined number of code word bits is six.

Claim 10

Apparatus as defined in claim 5 wherein said means for generating said code word from said block of bits includes a feedback shift register (501).

Claim 11

Apparatus as defined in claims 1 or 3 wherein said means for inserting includes means (306) for generating a timing signal (CRC BIT SYNC) including pulses concurrent with said code word bits (CRC BITS).

Claim 12

Apparatus as defined in claim 8 wherein said code word generating means (301) includes means (501) for generating said code word bits from a block (ESF) having a predetermined number of bits of the time division multiplexed signal (XTDM) and means (502) for serially supplying said code word bits to said means for inserting during a next subsequent block of bits of the time division multiplexed signal.

Claim 13

Apparatus as defined in claim 9 wherein said predetermined additional bit positions are predetermined framing bit positions.

Claim 14

Apparatus as defined in claim 10 wherein said means for inserting includes means (301, 304) responsive to said timing signal pulses (CRC BIT SYNC) and said code word bits (CRC BITS) for inserting said code word bits in said predetermined framing bit positions.

Claim 15

Apparatus as defined in claims 2 or 3 wherein said means for monitoring further includes means (705) for generating a timing signal (CRC BIT SYNC) having pulses concurrent with said code word bits (CRC BITS), wherein said code word generating means (702) includes means for generating said code word bits from a block having a predetermined number of bits of the time division multiplexed signal and means for serially supplying said code word bits during a next subsequent block of bits of the time division multiplexed signal, and wherein said comparing means (703) is responsive to said bits of the received time division multiplexed signal, to said code word bits, and to said timing signal pulses for generating said error indications (CRC BLOCK ERRORS).

Claim 20

Apparatus as defined in claim 2 wherein said means for monitoring further includes means for utilizing said error indications to monitor transmission performance. .Iaddend. .Iadd.16. Apparatus as defined in claim 10 wherein said means for monitoring further includes means for utilizing said error indications to monitor transmission performance. .Iaddend. .Iadd.17. Apparatus as defined in claim 12 wherein said means for monitoring further includes means for utilizing said error indications

Claim 21

to monitor transmission performance. .Iaddend. .Iadd.18. Apparatus for transmitting and receiving time division multiplexed signals including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (300) for formatting the time division multiplexed signal (XTDM) including means (310) responsive to bits in a block of bits of the time division multiplexed signal (XTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, and means (301, 304-306) for inserting said code word bits in predetermined ones of the additional bit positions of a subsequent block of bits of the time division multiplexed signal being transmitted to monitor errors in transmission; and means (700) for monitoring a received time division multiplexed signal including means (702) responsive to bits of a block of bits of the received time division multiplexed signal (RTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, means (703) for comparing said code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate error indications, and means (704) for utilizing said error indications to monitor transmission performance. .Iaddend. .Iadd.19. A method for monitoring errors in a received time division multiplexed signal including a series of blocks of bits each block including a plurality of data bits and a plurality of additional bit positions, the method comprising the steps of: generating a code word having a predetermined number of bits less in number than the plurality of additional bit positions from bits of a block of bits of the time division multiplexed signal in accordance with a prescribed criterion, comparing the code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate errors indications; and utilizing said error indications to monitor transmission performance. .Iaddend.

Claim 22

to monitor transmission performance. .Iaddend. .Iadd.18. Apparatus for transmitting and receiving time division multiplexed signals including a series of blocks of bits, each block including a plurality of data bits and a plurality of additional bit positions, characterized by means (300) for formatting the time division multiplexed signal (XTDM) including means (310) responsive to bits in a block of bits of the time division multiplexed signal (XTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, and means (301, 304-306) for inserting said code word bits in predetermined ones of the additional bit positions of a subsequent block of bits of the time division multiplexed signal being transmitted to monitor errors in transmission; and means (700) for monitoring a received time division multiplexed signal including means (702) responsive to bits of a block of bits of the received time division multiplexed signal (RTDM) for generating in accordance with a prescribed criterion a code word (CRC BITS) having a predetermined number of bits less in number than the plurality of additional bit positions, means (703) for comparing said code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate error indications, and means (704) for utilizing said error indications to monitor transmission performance. .Iaddend. .Iadd.19. A method for monitoring errors in a received time division multiplexed signal including a series of blocks of bits each block including a plurality of data bits and a plurality of additional bit positions, the method comprising the steps of: generating a code word having a predetermined number of bits less in number than the plurality of additional bit positions from bits of a block of bits of the time division multiplexed signal in accordance with a prescribed criterion, comparing the code word bits with bits of a subsequent received block of bits of the time division multiplexed signal to generate errors indications; and utilizing said error indications to monitor transmission performance. .Iaddend.