Bit demultiplexor for demultiplexing a serial data stream

• US 5,526,361 A
• Filed: 07/01/1993
• Issued: 06/11/1996
• Est. Priority Date: 07/01/1992
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Hedberg, Mats O. J.
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US08/084,619
• Time in Patent Office: 1,076 Days
• Field of Search: 370/84, 370/100.1, 370/105.1, 370/105.3, 370/108, 370/112, 375/371, 375/373, 375/376, 327/113, 327/119, 327/120, 327/141, 327/144, 327/152, 327/153, 327/155, 327/156, 327/158, 327/159, 327/161
• US Class Current: 370/518
• CPC Class Codes: H03K 5/00006 Changing the frequency modulating pulses H03K7/00; frequency dividers H03K21/00 - H03K29/00; additive or subtractive mixing of two pulse rates into one G06F7/605; pulse rate dividers G06F7/68
• CPC Class Codes: H03K 5/135 by the use of time reference signals, e.g. clock signals
• CPC Class Codes: H03K 5/1504 using a chain of active delay devices H03K5/15053 takes precedence
• CPC Class Codes: H04J 3/047 Distributors with transistors or integrated circuits
• CPC Class Codes: H04L 7/0337 Selecting between two or more discretely delayed clocks or selecting between two or more discretely delayed received code signals

Abstract

A bit demultiplexing circuit is disclosed including an internal clock generator which, by a reference clock, generates a number of accurately mutually time delayed clock signals. Clock aligning devices are controlled by incoming serial data for providing, by the time delayed clock signals, a number of differently phase clock signals, the phase positions of which are set in dependence on the phase position of incoming data. First demultiplexing devices clock, by the differently phased clock signals, incoming serial data to a parallel data flow. Second demultiplexing devices align, by one of the differently phased clock signals, this data flow to outgoing parallel data. A bit multiplexor circuit is also disclosed and includes an internal clock, an aligner, a delay device, and a multiplexor.

Claims

1. A bit demultiplexor for demultiplexing a serial data stream comprising:

internal clock means for generating a plurality of mutually time-delayed clock signals from a reference clock signal;

aligning means, responsive to the serial data stream and the plurality of mutually time-delayed clock signals, for generating a plurality of differently phased clock signals, wherein the phases of the plurality of differently phased clock signals are based on the serial data stream'"'"'s phase and creating a signal with a desired phase;

a delay circuit which receives said signal with a desired phase for imparting to the signal a successively increasing phase shift, and outputs said successively phase shifted signals as said differently phased clock signals;

control means which senses the phase positions of incoming data and of said successively phase shifted signals, for providing a control signal for the generation of said signal with said desired phase;

first demultiplexing means, responsive to the plurality of differently phased clock signals, for converting the serial data stream into a plurality of parallel data streams; and

second demultiplexing means, responsive to the plurality of differently phased clock signals, for mutually aligning the plurality of parallel data streams.

2. A circuit according to claim 1, wherein said clock aligning means comprises:

phase correcting means including selector means for selecting two clock signals from said mutually time delayed clock signals, between the phases of which a desired output phase from said phase correcting means is situated, and mixing means for mixing said two selected clock signals for generating the signal with the desired phase.

3. A circuit according to claim 2, wherein said control signal to said phase correcting means is obtained via a digital filter.

4. A bit multiplexor circuit, comprising:

an internal clock means for generating a plurality of mutually time delayed clock signals from a reference clock signal;

aligning means responsive to one of said clock signals, for aligning all incoming parallel data bits with respect to said clock;

delay means, responsive to another one of said clock signals, for delaying a number of said data bits; and

multiplexing means for multiplexing the aligned and delayed data bits by means of time delayed clocks, wherein

the internal clock means includes

phase shifting means for imparting to signals from a reference clock a successively increasing phase shift, said phase shifting means having a plurality of outputs for outputting said successively phase shifted signals,

first combining means for combining said phase shifted signals in groups to obtain a plurality of clock phases with a length corresponding to the phase shift between the outputs of the corresponding group and a frequency equal to a frequency of said reference clock, and

second combining means for combining clock phases while maintaining the pulse length to obtain an outgoing clock signal which has a frequency that is a multiple of said reference clock frequency, wherein

the outputs of said aligning means and said delay means are connected for transferring said aligned and delayed data bits to data inputs of a selector, said selector also having a number of control inputs and a data output, and

the outputs from said first combining means are connected for transferring said clock phases to the control inputs of said selector, via which said clock phases control said selector so that one data input at a time is connected to said data output of said selector, said outgoing clock signal forming said clock of said outgoing data stream.

5. A circuit according to claim 4, wherein said internal clock means includes at least one phase locked delay line circuit which extracts an accurate phase clock from said clock means.

6. A circuit according to claim 5, wherein said delay line circuit comprises:

said phase shifting means for imparting to signals from said reference clock a successively increasing phase shift, said phase shifting means having a plurality of outputs for outputting such successively phase shifted signals;

said first combining means for combining said phase shifted signals in groups for obtaining a number of pulses with a length corresponding to the phase shift between the outputs of the corresponding group and a frequency equal to a frequency of said reference signal;

said second combining means for combining said pulses while maintaining the pulse length for obtaining a plurality of pulse signal with a frequency that is a multiple of said reference clock frequency; and

a clock signal generating circuit for generating, from said pulse signals, said mutually time delayed clock signals in the form of a desired number of clock signals with a desired mutual phase shift.

7. A circuit according to claim 4, wherein said internal clock means and said delay means of said clock aligning means include at least one phase locked delay line circuit which extracts an accurate phase clock from said clock means.