Accession Number : ADD018260

Title :   Digital Circuit for Generating a Clock Signal.

Descriptive Note : Patent, Filed 31 Jul 95, patented 23 Jul 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Snelgrove, Andrew H

Report Date : 23 Jul 1996

Pagination or Media Count : 6

Abstract : A digital circuit comprising a pair of D Flip-Flops which synchronize an incoming NRZ L serial data stream to an external ten megahertz clock signal. The combination of a third D Flip-Flop and an EXCLUSIVE-NOR gate generates a clear pulse whenever a change of state occurs within the synchronized serial data stream. This clear pulse is supplied to a ten state machine resetting the state machine to state SO. When the state machine transition to state 54 the state machine generates an enable signal which is supplied to a toggle Flip-Flop enabling the Flip-Flop allowing the Flip-Flop to change state. The ten megahertz clock signal then clocks the toggle Flip-Flop causing the Flip-Flop to change state. At state S9 the state machine again provides an enable signal to the toggle Flip-Flop enabling the toggle Flip-Flop which allows the ten megahertz clock signal to change the state of the output of the toggle Flip-Flop. This results in one megahertz clock signal at the output of the toggle Flip-Flop which is synchronized to the incoming serial data stream.

Descriptors :   *FLIP FLOP CIRCUITS, *PATENTS, *TIMING CIRCUITS, TOGGLE SWITCHES, NOR GATES, RELAXATION OSCILLATORS, SYNCHRONIZING SWITCHES

Subject Categories : Electrical and Electronic Equipment
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE