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Phase-Locked Oscillator Or a State Estimator for Tracking Sinusoidal Voltage Versus Position Signals

IP.com Disclosure Number: IPCOM000119257D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Belser, KA: AUTHOR

Abstract

The blocks in the dotted lines labeled 18 comprise a voltage-controlled oscillator that can work from zero frequency to some high frequency. The blocks 1, 2, 3, and 4 solve the differential equation for a sine wave, ddx/ddt + w*w*x = 0, where w is the output of the adder 14. The multipliers 5 control the amplitude of the sine wave by creating either positive (increasing amplitude) or negative (decreasing amplitude) eigen values for the integrators 3 that are used in the differential equation solution. Blocks 6, 7, and 17 take the square root of the sum of the squares of the outputs of the integrators 3. These outputs are a sine and cosine wave. Sine squared plus cosine squared equals the amplitude of the sine wave. The block 8 compares the sine wave amplitude to a desired amplitude.

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Phase-Locked Oscillator Or a State Estimator for Tracking Sinusoidal
Voltage Versus Position Signals

      The blocks in the dotted lines labeled 18 comprise a
voltage-controlled oscillator that can work from zero frequency to
some high frequency.  The blocks 1, 2, 3, and 4 solve the
differential equation for a sine wave, ddx/ddt + w*w*x = 0, where w
is the output of the adder 14.  The multipliers 5 control the
amplitude of the sine wave by creating either positive (increasing
amplitude) or negative (decreasing amplitude) eigen values for the
integrators 3 that are used in the differential equation solution.
Blocks 6, 7, and 17 take the square root of the sum of the squares
of the outputs of the integrators 3.  These outputs are a sine and
cosine wave.  Sine squared plus cosine squared equals the amplitude
of the sine wave.  The block 8 compares the sine wave amplitude to a
desired amplitude.  The error in amplitude is multiplied by a gain R
9 and is fed back to control the amplitude of the sine waves using
multipliers 5.

      The blocks in the dotted lines labeled 19 comprise a phase de
tector that uses the fact that both the sine and cosine waves are
available from the voltage-controlled oscillator 18.  This phase
detector will work from zero frequency up to some high frequency.
The range of allowable relative phase error for which the phase
detector gives a correct polarity error signal for all phase angles
of the input sine wave is about +/- 45 degrees....