Browse Prior Art Database

Phase Lock Indicator for Variable Frequency Oscillator

IP.com Disclosure Number: IPCOM000111217D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Chen, SC: AUTHOR [+3]

Abstract

Disclosed is a Phase Lock Indicator (PLI) for use in the manufacture of Variable Frequency Oscillators (VFO) to ensure VFO AC characteristics and enhance the VFO's performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Phase Lock Indicator for Variable Frequency Oscillator

      Disclosed is a Phase Lock Indicator (PLI) for use in the
manufacture of Variable Frequency Oscillators (VFO) to ensure VFO AC
characteristics and enhance the VFO's performance.

      A VFO receives and synchronizes to a source data stream in two
stages.  During fast synchronization, the VFO synchronizes rapidly to
a new source to acquire frequency and phase lock to the data stream.
Then during slow synchronization it proceeds to contain timing
jitter.

      A Device controller controls the time permitted for completion
of each of these stages.  But prior to the present invention there
was no method for determining when the VFO had completed fast
synchronization.  Thus the device controller permitted fast sync to
continue for a worst-case duration of time.  The present invention
permits the VFO to signal the device controller when it has completed
fast sync so that the duration of the entire synchronization process
is minimized.

      The proposed PLI consists of two functional blocks.  The first
block comprises the VFO with a Variable Data Window (VFO/VDW) and has
been described in [*].  This block has a source data input, and
provides a VFO clock and Data Synchronized or "Standardized" to The
Clock (DSTC) as outputs.  The second block is a Synchronization
Pattern Detector (SPD).  The SPD receives the VFO clock and DSTC as
inputs, and provides a control output which activates when fast
s...