The principles of a new real-time channel evaluation (RTCE) technique applicable to digital communication channels are described. At the transmitter, the statistical properties of the data are specified by appropriate source coding. At the receiver, the corresponding statistical properties of the received data are monitored continuously. Discrepancies between the specified transmitted data statistics and those actually observed at the receiver are then analysed to yield information on channel state. An implementation of the technique employing variable-rate T-codes for source coding is described, together with its performance over an additive white Gaussian noise (AWGN) channel and a channel with memory. It is shown that SRTCE techniques are particularly applicable to communication channels where the effect of noise is severe.