Automatic Center Frequency and Span Setting in Test Instruments

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Solution Overview

Problem

Modern test and measurement instruments require manual adjustment of display center frequency and span settings to highlight areas of interest in frequency domain waveforms, which is tedious and time-consuming.

Innovation Solution

A processor in the test and measurement instrument automatically adjusts the display center frequency and span settings by locating a primary peak in the input signal, maintaining a constant ratio between span and resolution bandwidth, and iteratively refining the adjustments until the peak bandwidth meets a threshold, thereby generating a processed waveform signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual adjustment of display center frequency and span settings is used, then the user can highlight areas of interest in the waveform, but the process becomes tedious and time-consuming

Engineering Contradiction:
Improveease of operationVSAvoidtime required for analysis
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system automatically performs frequency domain analysis and adjusts display settings without requiring user intervention. The processor independently identifies peaks, determines optimal span values, and configures display parameters, allowing the instrument to serve itself rather than requiring manual operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system automatically changes display parameters (center frequency, span, resolution bandwidth) based on the analyzed signal characteristics. By dynamically adjusting these parameters according to detected peak frequencies and bandwidths, the system eliminates manual parameter setting while optimizing the display for areas of interest.

Inventive Principle:
Principle #35Parameter changes

2Extent of automation

If the entire frequency range is searched to find the highest peak, then automatic center frequency setting can be achieved, but the process becomes more complex

Engineering Contradiction:
Improveextent of automationVSAvoidcomplexity of automatic tuning process
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The frequency domain analysis is segmented into discrete frequency bins or channels that can be independently evaluated. The processor examines each frequency component separately to identify peaks, allowing systematic automation without requiring complex continuous analysis across the entire frequency range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces manual mechanical adjustment mechanisms with automated digital signal processing. Instead of physical knobs and switches for frequency and span adjustment, the system uses digital algorithms to automatically detect peaks and calculate optimal display parameters, substituting mechanical user interaction with computational automation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2743711B1Automatic centre frequency and span setting in a test and measurement instrument
Publication Date: 2018.08.08 TEKTRONIX INC
  • EP2743711B1 patent drawingFigure 1
  • EP2743711B1 patent drawingFigure 2
  • EP2743711B1 patent drawingFigure 3

AI summary

A test and measurement instrument having initial display center frequency and span settings and configured to process an input signal is disclosed. The test and measurement instrument includes a processor configured to digitize the input signal and locate a primary peak (50) and determine a primary peak center frequency of the input signal. The processor is configured to adjust the initial display center frequency setting based on the primary peak center frequency. The processor is configured to perform a bandwidth comparison by comparing a bandwidth of the primary peak at a peak bandwidth test level (52) to a peak bandwidth threshold. The processor is configured to adjust the initial span setting based on the bandwidth comparison and generate a processed waveform signal using the adjusted display center frequency and span settings.