Abstract: A method and apparatus for removing glitches, interference or noise from a clock signal are provided by the present invention. In accordance with the invention, a glitch-ridden clock signal is monitored to determine when a transition in the glitch ridden clock signal occurs. When a transition occurs, a counter is initiated in accordance with a second high-speed clock signal. The value of this counter is compared to a compare value. The compare value is selected to approximately equal the expected period of the glitch-ridden clock signal. If the counter value equals the compare value, it is assumed that the transition was a valid transition and the transition is carried through and output as a glitch-free clock signal. However, if a transition occurs before the count value equals the counter compare value, it is assumed that the transition is invalid and no transition is carried to the glitch-free clock output.

Abstract: A method and apparatus for removing glitches, interference or noise from a clock signal are provided by the present invention. In accordance with the invention, a glitch-ridden clock signal is monitored to determine when a transition in the glitch ridden clock signal occurs. When a transition occurs, a counter is initiated in accordance with a second high-speed clock signal. The value of this counter is compared to a compare value. The compare value is selected to approximately equal the expected period of the glitch-ridden clock signal. If the counter value equals the compare value, it is assumed that the transition was a valid transition and the transition is carried through and output as a glitch-free clock signal. However, if a transition occurs before the count value equals the counter compare value, it is assumed that the transition is invalid and no transition is carried to the glitch-free clock output.

Abstract: The currently defined industry standard framing structure for 2B1Q ISDN signaling, at 160 kilobaud, provides 128 kbps for a customer (B1, B2) data channel, and 16 kbps for a data (D) channel. Of the remaining 16 kbps non payload bandwidth, 4 kbps are used for overhead maintenance data. Eight kbps of the remaining 12 kbps of non payload bandwidth, that customarily transport a repeated framing pattern, are usurped for the transport of an auxiliary compressed (from 64 KHz to 8 KHz) digitized voice POTS channel, that is sufficient to transport toll quality voice. The remaining framing pattern bandwidth is adequate prevent an unacceptable reduction in bit error rate.

Abstract: A wander reduction mechanism in an HDSL pulse-stuffing synchronization system provides a more precise measure of the phase of the incoming asynchronous signal than is obtained in conventional schemes, in which the only information available is the presence or absence of stuffing pulses. An auxiliary phase comparator and phase adjuster are incorporated into the synchronizer-multiplexer to generate a reference data clock (derived from the synchronized data clock), so that the incoming unsynchronized data clock can be tracked. As the clock is iteratively phase-adjusted, the respective changes are accumulated. At the end of a prescribed measurement interval, the net contents of the accumulator are encoded and transported over the synchronous digital data communication channel to the receiver.