Signal Processing Method for Noise Figure Measurement Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing noise reduction techniques in measurement instruments cannot distinguish between noise sources, inadvertently reducing the noise figure of the device under test, making precise measurement challenging and costly.
Innovation Solution
A signal processing method that involves capturing IQ measurement sets, determining IQ averages, and calculating noise vectors to isolate and suppress noise contributions from all sources, allowing for precise determination of the device under test's noise contribution using IQ and EVM averaging without separate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise reduction techniques are applied to reduce the overall noise level, then the noise level is reduced, but the noise generated by the device under test is also reduced making precise measurement impossible
Solution Approach 1:
The patent segments the noise measurement process into two distinct parts: first measuring the combined noise (device under test + measurement equipment) and then measuring the equipment noise separately. By subtracting the equipment noise from the combined noise, the patent isolates and precisely measures only the device under test's noise contribution, preventing the loss of measurement precision that would occur with blanket noise reduction techniques.
Solution Approach 2:
The patent extracts and separately measures the measurement equipment's noise contribution from the total noise signal. By taking out the equipment noise component through separate measurement and then subtracting it from the combined measurement, the patent recovers the pure device under test noise signal without the interference of equipment-generated noise, thereby maintaining measurement precision.
2Measurement precision
If high-quality measurement instruments with low inherent noise level are used, then measurement precision is improved, but the cost increases
Solution Approach 1:
The patent introduces an intermediary measurement process - a separate equipment noise measurement - that acts as a mediator to eliminate the need for expensive low-noise instruments. By measuring and subtracting the equipment noise contribution, the patent allows the use of standard, cost-effective measurement instruments while still achieving high measurement precision through mathematical separation of noise sources.
Solution Approach 2:
The patent changes the measurement parameter from directly measuring the device under test's noise with expensive low-noise equipment to measuring the equipment's noise contribution separately and then calculating the device noise through subtraction. This parameter change in the measurement approach enables the use of lower-cost instruments while maintaining measurement precision.
3Measurement precision
If separate measurements are performed for IQ averaging and EVM averaging, then measurement precision is improved, but the measurement time increases
Solution Approach 1:
The patent merges the IQ averaging and EVM averaging measurements into a single unified measurement process. By capturing one set of IQ measurement data that serves both averaging purposes simultaneously, the patent eliminates the need for separate measurement campaigns, thereby reducing measurement time while maintaining the precision benefits of both averaging techniques.
Solution Approach 2:
The patent makes the IQ measurement data universal by designing the measurement process so that a single set of captured IQ measurements can be used for both IQ averaging and EVM averaging calculations. This multi-functional use of the same measurement data eliminates redundant measurements and reduces overall measurement time while preserving measurement precision.
Data Source
AI summary
A signal processing method is provided for processing a digital input signal. The method may be carried out by a measurement instrument. The measurement instrument includes a signal input, a measurement circuit, and an analysis circuit. The signal processing method includes the steps of: receiving a digital input signal from a device under test; capturing a first number N1 of IQ measurement sets based on the received digital input signal, wherein each IQ measurement set comprises a plurality of IQ measurement points; determining an IQ average based on the captured IQ measurement sets, thereby obtaining an averaged signal; determining a second number N2 of noise vectors based on the averaged signal and based on the captured IQ measurement sets; and averaging over the determined noise vectors, thereby obtaining an averaged noise vector.