Multi-Tone Calibration for Reconstructed Signal Impairment Correction
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Solution Overview
Problem
Conventional real-time oscilloscopes have limited bandwidth, making it difficult to accurately capture input signals with frequency components exceeding the available channel bandwidth, and existing methods like frequency domain interleaving introduce undesirable signal impairments.
Innovation Solution
A method and system for calibrating reconstructed signals from multiple sub-signals by injecting a calibration signal with multiple tones, dividing the input signal into sub-signals with overlapping frequency bands, performing frequency translations, digitizing, and quantifying impairments to correct phase and magnitude differences, allowing for accurate reconstruction of the original signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequency domain interleaving is used to capture signals with bandwidth greater than the oscilloscope channel bandwidth, then the bandwidth capability is improved, but signal impairments are introduced
Solution Approach 1:
The input signal is divided into multiple sub-signals, each within the bandwidth of an individual oscilloscope channel. This segmentation allows the system to capture signals with total bandwidth exceeding the channel bandwidth by processing multiple frequency bands simultaneously through parallel channels.
Solution Approach 2:
A calibration signal is injected into the input signal before it is divided into sub-signals. The calibration signal passes through the same processing path as the input signal, allowing the system to measure and quantify impairments introduced during the interleaving and reconstruction process. This feedback mechanism enables correction of the calibration signal to compensate for channel variations and signal impairments.
2Measurement precision
If multiple sub-signals are processed through separate oscilloscope channels, then the measurement precision for high bandwidth signals is improved, but the device complexity increases
Solution Approach 1:
The calibration signal serves multiple functions: it is used to quantify impairments in the sub-signal processing path, to calibrate the oscilloscope channels, and to verify the reconstruction accuracy. This multi-functionality reduces the need for separate calibration mechanisms and simplifies the overall system.
Solution Approach 2:
The system dynamically adjusts processing parameters based on the quantified impairments. By measuring the calibration signal through the same path as the input signal, the system can adaptively correct for channel variations, gain mismatches, and phase differences, improving measurement precision without requiring complex hardware modifications.
3Manufacturing precision
If the input signal is divided into sub-signals with overlapping frequency bands, then the reconstruction accuracy is improved, but the processing time increases
Solution Approach 1:
The calibration signal is injected and processed in advance, before the actual input signal measurement. By pre-quantifying the impairments through the calibration signal, the system can prepare correction data that will be applied during the reconstruction process, reducing the real-time processing burden and improving overall efficiency.
Data Source
AI summary
A method of calibrating a reconstructed signal from a plurality of sub-signals is provided. The method includes injecting a calibration signal having multiple tones into a received input signal; dividing the input signal into a first and second sub-signal, including an overlapping frequency band; performing a first frequency translation by converting frequency components of the second sub-signal; digitizing the first sub-signal and the frequency converted second sub-signal; performing a second frequency translation to reverse the first frequency translation to obtain a reconstructed second sub-signal; and quantifying impairments to the digital first sub-signal and reconstructed second sub-signal caused by differences in magnitude and phase of frequency components within the overlapping frequency band.