STEL-2060CR Datasheet | Intel

FEATURES s 45 Mbps Operating Rate s Constraint Length K = 7 G1 = 1718 G2 = 1338 FUNCTIONAL DESCRIPTION Convolutional encoding and Viterbi decoding are used to provide forward error correction (FEC) which improves digital munication performance over a noisy link. The STEL-2060C is a specialized product designed to perform this specific munications related function. At the encoder a stream of symbols is created which introduces a high degree of redundancy. This enables accurate decoding of the information despite a high symbol error rate resulting from an impaired munications link. The STEL-2060C contains a K = 7 Viterbi Decoder. The data inputs can be in offset binary or offset signed-magnitude formats, with 3-bit soft decision. Auto node sync is provided for applications where symbol uncertainty can occur. Rate 2 /3, 3/4, 4/5, 5/6, 6/7 and 7/8 punctured signals can be decoded, as well as non-punctured, Rate 1/2, signals. The polynomials and puncturing patterns used are industry standards. Depuncturing logic is incorporated into the decoder to provide automatic depuncturing of received data at rates 2/3, 3/4 and 7/8 when the puncturing patterns supported by the device are used. A BER monitor is also provided in the device, along with a circuit for puting the mean value of the BER over an extended period. These circuits operate with punctured codes as well as unpunctured. The STEL-2060C incorporates a descrambler for signals scrambled with the “Invert G2” algorithm. (With this method the G2 symbols are logically inverted at the encoder. This provides a very effective level of scrambling for the purpose of avoiding long strings of ones or zeroes in the transmitted signal using BPSK modulation.) s s s s s s s s s s s Multiple Rates: Rate 1/2 as well as Punctured codes at Rates 2/3 through 7/8 Internal Depuncturing Capability at Rates 2 /3, 3/4 and 7/8 Multiple Devices can be Multiplexed to Give Higher Data Rates Optimized Interface to Operate with BPSK and QPSK...