Abstract: A receiving modem is locked to a transmitting modem by employing a burst data and clock signal having an effective data rate compatible with the data rate of a receiving data set. The receive modem processes a transmitted analog signal as sent by the transmitting modem to provide a digital signal which is applied to an interpolation filter. The filter provides at an output a retimed signal. This retimed signal is monitored by a baud sync measurement circuit which detects the drift of baud transitions in the retimed interpolated signal to provide an output phase error signal. This phase error signal is used to control the filter coefficients of the interpolation filter for the next data block. In this manner the interpolation filter provides a newly retimed digital output signal according to the detected phase error. The output signal is demodulated and converted to a burst data and a burst clock signal for application to a receiving data set.