The Wideband Convolution Encoder (WCONV-ENC) contains a r=7/8, J=6, Na = 1176 self orthogonal systematic convolutional encoder. Currently, this encoder is being used for a 280 Mb/s input information rate and an output symbol rate of 320 Mb/s (I and Q outputs at 160 Mb/s). Implementation is such that much higher data rates can be achieved. Input ECL data and clock are processed and output I channel data, Q channel data and 8/7 information rate clock are provided as ECL outputs. Phase lock loop circuitry generates the internal processing clocks and the output clock signal. Rate 1/2, Na = 7 convolutional encoders have also been provided in various test modulators.