MJ1440

MJ1440 2 MBIT PCM SIGNALLING CIRCUIT MJ1440 HDB3 ENCODER/DECODER The 2.048 MBit PCM Signalling Circuits comprise a group of circuits which will perform the common signalling and error detection functions for a 2.048 MBit PCM transmission link operating to the appropriate CCITT recommendations. The circuits are fabricated in N-channel metal gate MOS and operate from a single 5 volt supply, relevant inputs and outputs are TTL compatible. The MJ 1440 is an encoder/decoder for the pseudoternary transmission code, HDB3 (CCITT Orange Book Vol 111.2 Annex to Rec. G703). The device encodes and decodes simultaneously and asynchronously. Error monitoring functions are provided to detect violations of HDB3 coding, all ones detection and loss of input (all zeroes detection). In addition a loop back function is provided for terminal testing. NRZ DATA IN 1 CLOCK (ENCODER) 1 LOSS OF INPUT 3 NRZ DATA OUT 4 CLOCK (DECODER) 5 11 LOOP TEST ENABLE RESETAIS 6 ~7 GROUND L8..-_ _..9... ERROR DG16 Fig. 1 Pin connections FEATURES 5v ± 5% Supply -50mA Max HDB3 Encoding and Decoding to CCITT rec. G703. Asynchronous Operation. Simultaneous Encoding and Decoding. Clock Recovery Signal Generated from Incoming HDB3 Data. Loop Back Control. HDB3 Error Monitor 'All Ones' Error Monitor Loss of Input Alarm (All Zeros Detector). Decode Data in NRZ Form. ABSOLUTE MAXIMUM RATINGS The absolute maximum ratings are limiting values above which operating life may be shortened or specif...