Dynamic Probe Clamping for Oscilloscope Saturation Prevention

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Solution Overview

Problem

Test and measurement systems face challenges in measuring signals with wide voltage swings, particularly in capturing small voltage components due to oscilloscope input saturation, which limits vertical sensitivity and recovery time.

Innovation Solution

Incorporating a user-selectable or dynamically controlled output clamping/limiting feature in the probe or accessory to restrict the output voltage swing within the oscilloscope's linear input range, preventing saturation and allowing increased vertical sensitivity without overdriving the oscilloscope.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the oscilloscope vertical sensitivity is increased to measure small voltage components, then measurement precision is improved, but the oscilloscope input becomes overdriven and saturated

Engineering Contradiction:

Improvemeasurement precisionVSAvoidoscilloscope input saturation

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A clamping circuit is introduced as an intermediary device between the probe output and the oscilloscope input. This circuit actively monitors the oscilloscope input voltage and applies clamping action when the voltage exceeds predefined thresholds, preventing overdrive saturation while allowing the oscilloscope to operate at high vertical sensitivity for measuring small voltage components

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the probe output voltage swing is increased to capture large signals, then the ability to measure large voltage swings is improved, but the oscilloscope input range is exceeded causing distortion

Engineering Contradiction:

Improveability to measure large voltage swingsVSAvoidsignal integrity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The clamping circuit operates dynamically by continuously monitoring the instantaneous voltage level at the oscilloscope input and applying clamping action only when thresholds are exceeded. This dynamic operation allows the system to accommodate both large voltage swings and small voltage components without distortion, maintaining signal integrity across varying signal conditions

Inventive Principle:

Principle #15Dynamics

3Reliability

If the oscilloscope input range is reduced to prevent saturation, then reliability is improved, but the ability to measure signals with wide voltage swings is reduced

Engineering Contradiction:

Improveoscilloscope input saturation preventionVSAvoidmeasurement range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The clamping circuit employs feedback mechanisms to monitor the oscilloscope input voltage and adjust its clamping action accordingly. This feedback control allows the system to maintain reliable operation by preventing saturation while preserving the ability to measure signals with wide voltage swings, as the clamping action is applied only when necessary to prevent exceeding the oscilloscope input range

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3211434B1An electrical test and measurement system with dynamic control of a probe output clamping and a corresponding method

Publication Date: 2024.10.09 TEKTRONIX INC

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AI summary

A probe or accessory for use with an electrical test and measurement instrument can include an input to receive an input signal from a device under test (DUT), a clamp control unit or oscilloscope to apply a clamping/limiting level to the input signal to generate an output signal, and/or a control unit output port to provide the clamped/limited output signal to an oscilloscope.