Repeated Cycle Square Wave Voltammetry for AC Interference Rejection

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Solution Overview

Problem

Conventional Square Wave Voltammetry (SWV) measurements are susceptible to interference from AC power lines, particularly in industrial or field measurement applications where shielded enclosures and careful laboratory practices are not feasible.

Innovation Solution

The implementation of Repeated Cycle Square Wave Voltammetry (RCSWV) involves replacing a single cycle of conventional SWV with an integer number of shorter cycles, such that the total duration equals an even integer number of power line cycles. This approach allows for higher modulation frequencies while maintaining immunity to AC line interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional SWV uses a single cycle with low modulation frequency, then immunity to AC line interference is maintained, but measurement time increases and productivity decreases

Engineering Contradiction:

Improveimmunity to AC line interferenceVSAvoidmeasurement speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The single SWV cycle is segmented into multiple repeated cycles. Each cycle applies square wave modulations at higher frequencies, and the current responses are averaged across all cycles. This segmentation allows using higher modulation frequencies while maintaining interference rejection through averaging, thus resolving the contradiction between measurement speed and AC line interference immunity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic repetition of square wave modulation cycles. By performing multiple periodic cycles with equal voltage amplitude and averaging the current responses, the method achieves higher effective modulation frequency while the periodic averaging structure maintains immunity to AC line interference, resolving the speed-reliability contradiction.

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If shielded enclosures and careful laboratory practices are used, then AC line interference is reduced, but device complexity and ease of operation are compromised

Engineering Contradiction:

ImproveAC line interferenceVSAvoidmeasurement system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for physical shielding and complex laboratory practices by using a signal processing approach. The repeated cycle SWV method with averaging inherently rejects AC line interference through its mathematical structure, removing the requirement for shielded enclosures and simplifying both device complexity and ease of operation while maintaining interference rejection.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If higher modulation frequencies are used in SWV, then measurement sensitivity and resolution improve, but susceptibility to AC line interference increases

Engineering Contradiction:

Improvevoltammetry resolutionVSAvoidAC line interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The measurement is segmented into multiple repeated cycles, each operating at high modulation frequency for improved precision. The segmentation allows high-frequency operation while the averaging across segmented cycles suppresses AC line interference, resolving the contradiction between measurement precision and interference susceptibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

By using periodic repetition of cycles at high modulation frequency with averaging, the patent achieves improved measurement precision through higher frequencies while the periodic averaging structure provides inherent rejection of AC line interference, resolving the precision-interference contradiction.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

RCSWV effectively reduces the impact of AC line interference, enabling the use of higher modulation frequencies and improving the robustness of measurements, even in challenging environments.

Implementation Method 1

applying a stimulus voltage step to the aqueous sample, wherein the stimulus voltage comprises a staircase voltage

Methodology Applied

Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 2

measuring a resultant current output resulting from the stimulus voltage, wherein the measuring comprises square wave voltammetry

Methodology Applied

Scientific EffectSquare wave voltammetry:

Data Source

PatentUS12222319B2Repeated cycles square wave voltammetry

Publication Date: 2025.02.11 HACH

AI summary

An embodiment provides a method for measuring a component of an aqueous sample using square wave voltammetry, including: introducing the aqueous sample to a chamber of a square wave voltammetry apparatus; applying a stimulus voltage step to the aqueous sample, wherein the stimulus voltage comprises a staircase voltage, wherein each step of the staircase voltage defines a group and comprises two or more repeated square wave modulations of equal voltage amplitude; measuring a resultant current output resulting from the stimulus voltage, wherein the measuring comprises square wave voltammetry; and averaging the resultant current output across at least two or more cycles of each group. Other aspects are described and claimed.