Data circuit terminating equipment (dce) including timing arrangements

Abstract

Data Circuit Terminating Equipment (DCE) allows the connection of a Data Terminal Equipment (DTE) to a telecommunication line. The DCE includes timing elements for providing the DTE with any desired transmitter signal element timing and any desired receiver signal element timing. The timing elements include processing elements for computing a sequence of digital values A(n) and for deriving therefrom a corresponding sequence of interrupt signals T(n). The receiver signal element timing, the transmitter signal element timing, the transmit sampling clock pulsing the D/A converter and the receive sampling clock pulsing the A/D converter are all controlled by different sequences of digital values computed by the processing elements. By generating appropriate sequences of digital values, the processing elements can provide any desired relationship between the different clocks to satisfy a transmit signal element timing slaved to the receiver signal element timing in synchronous mode, or on an external clock in tailing mode. The timing elements can also provide a transmit sampling clock slaved to the receive sampling clock in order to perform powerful digital echo cancellation techniques. Moreover, the processing elements can control the persistence of a received bit, which if a STOP bit, can allow the compensation of the DTE and the line data throughput difference.