Synchronized Interference Signals in Measurement Instruments

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Solution Overview

Problem

High-accuracy electrical measurement instruments face interference from signals generated by their own power supplies and digital control circuitry, particularly in miniaturized or densely arranged configurations, making it challenging to maintain measurement integrity.

Innovation Solution

The instrument incorporates a synchronization mechanism where the interference signal frequency is an integer multiple of the reciprocal of the measurement aperture and is phase-locked with it, minimizing interference effects by aligning these frequencies with the sensitivity nulls of the measurement section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If power supplies and digital control circuitry are integrated into the measurement instrument, then the instrument can be miniaturized and densely arranged, but interference signals are generated that adversely affect measurement accuracy

Engineering Contradiction:

Improveinstrument sizeVSAvoidmeasurement accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The measurement section operates in periodic time windows (measurement apertures) rather than continuously. By synchronizing the support section's interference signal frequency to be an integer multiple of the reciprocal of the measurement aperture duration and phase-locking it, the interference signals are pushed to frequency nulls where they do not affect measurements, enabling miniaturization without sacrificing accuracy

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The invention changes the frequency parameter of the interference signals by synchronizing the support section to operate at frequencies that are integer multiples of the reciprocal of the measurement aperture. This parameter transformation moves interference signals to null frequencies, resolving the contradiction between miniaturization and measurement precision

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If power supplies and digital control circuitry are placed close to the measurement section, then device complexity is reduced, but interference from these sections increases

Engineering Contradiction:

Improveinstrument configurationVSAvoidinterference signal

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

Instead of trying to eliminate or isolate the interference signals from the power supply and digital control circuitry, the invention synchronizes these sections so that their interference signals occur at frequency nulls. This converts the harmful interference into a beneficial arrangement where the inevitable interference signals do not affect measurements, allowing dense integration without compromising performance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS7683650B1Measurement instrument with synchronized interference signals

Publication Date: 2010.03.23 KEITHLEY INSTRUMENTS INC

AI summary

An instrument for measuring electrical parameters includes a measurement section having a measurement aperture; and a support section providing at least one of power and digital control for the measurement section. The support section has an interference signal frequency, wherein the interference frequency is an integer multiple of the reciprocal of the measurement aperture and the measurement aperture and the interference signal are phase-locked. As a result, the effect of the interference signal on electrical parameters measured is minimized.