Measurement System With Periodic Averaging Circuit
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Solution Overview
Problem
Existing measurement systems face challenges in performing fast and accurate wideband calibration over a wide frequency range, particularly when using vector network analyzers for frequency converting measurements.
Innovation Solution
The measurement system incorporates a signal source providing a repetitive signal, an analog-to-digital converter, a numerically controlled oscillator, a mixing stage, and a periodic averaging circuit, along with a processing circuit that performs Fourier transforms to determine the frequency response of a device under test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement techniques are used for wideband calibration, then measurement accuracy can be maintained, but measurement time becomes excessively long
Solution Approach 1:
The patent applies periodic action by using a repetitive calibration signal with a defined repetition frequency. The signal is repeated multiple times and averaged periodically, which accelerates the measurement process while maintaining accuracy. The periodic nature of the signal allows for efficient correlation processing and frequency domain analysis, resolving the contradiction between fast measurement and accurate frequency response determination.
Solution Approach 2:
The patent implements preliminary action by pre-defining buffer lengths that are integer multiples of the signal period before measurement begins. This pre-planning of buffer structures and correlation windows allows the measurement system to process data efficiently without real-time computation delays, enabling fast wideband calibration while preserving measurement precision through proper signal averaging.
2Measurement precision
If wideband calibration signal with low spectral power density is used, then frequency response accuracy is improved, but number of samples required increases leading to longer processing time
Solution Approach 1:
The patent replaces traditional time-domain averaging with frequency-domain correlation processing. By transforming the measurement approach to use cross-correlation in the frequency domain, the system can efficiently process wideband signals with low spectral power density without requiring excessive samples. This substitution of processing methodology resolves the contradiction between maintaining signal accuracy and improving measurement speed.
Solution Approach 2:
The patent changes the processing parameter from time-domain averaging to frequency-domain correlation. This parameter transformation allows the system to extract frequency response information more efficiently from wideband calibration signals, reducing the number of samples needed while maintaining measurement precision across the entire frequency range.
3Adaptability or versatility
If frequency converting measurement is performed, then wide frequency range coverage is achieved, but calibration complexity increases
Solution Approach 1:
The patent implements a universal calibration approach that works across wide frequency ranges by using frequency-domain cross-correlation as a multi-functional processing method. The same correlation-based algorithm handles both frequency conversion and frequency response measurement, reducing calibration complexity while maintaining wide frequency range coverage through a single unified measurement technique.
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
This configuration enables real-time frequency response determination and calibration over a wide frequency range up to 100 GHz, improving signal-to-noise ratio and reducing measurement time.
Implementation Method 1
the numerically controlled oscillator and the mixing stage together are configured to frequency shift the samples
Implementation Method 2
the periodic averaging circuit is configured to sum or average the samples obtained over a defined number of buffer lengths, thereby providing at least one output signal
Implementation Method 3
a processing circuit that is configured to perform Fourier transform on the at least one output signal, thereby converting the at least one output signal to frequency domain
Data Source
Figure 1~2
AI summary
The invention relates to a measurement system (10) with a signal source (12), an analog to digital converter (24), a numerically controlled oscillator (28) and a mixing stage (30). The measurement system (10) further comprises a periodic averaging circuit in hardware (38) located downstream of the numerically controlled oscillator (28) and the mixing stage (30), wherein the periodic averaging circuit in hardware (38) is configured to sum or average samples obtained over a defined number of buffer lengths, thereby providing at least one output signal. The measurement system (10) has a processing circuit (42) configured to perform a Fourier transform on the output signal. The numerically controlled oscillator (28) together with the mixing stage (30) are configured to shift the frequency of the samples such that picket signal portions of the output signal, processed by the processing circuit (42), are associated with frequency bins in the frequency domain.