Htu-c clocking from a single source

Abstract

An apparatus and method are provided for generating a plurality of data frames in a DSL modem configured as an HTU-C device using a single clock source. The technique of the present invention generates a data clock signal by combining a first clock signal provided by a clock source and a receiver overhead signal provided by framing circuitry for indicating the insertion of frame overhead bits into a data frame. The generated data clock signal has the characteristics such that, while the receiver overhead signal is inactive, the data clock signal is active at a frequency substantially equal to frequency of the first clock signal, and while the receiver overhead signal is active, the data clock signal is inactive. The result of this technique is that incoming data is clocked into the data frame at a data rate substantially equal to the frequency of the first clock signal only during time intervals when frame overhead bits are not being inserted into the one data frame. By using a single clock source to provide both the data rate and signaling rate, a reduction in cost, space, complexity, and power consumption of the HTU-C device may be achieved as compared to conventional devices.