Oscilloscope Signal Post-Processing Circuit Virtual Frequency Span
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Solution Overview
Problem
Existing oscilloscopes require significant resources and are inflexible when selecting a specific frequency range for signal analysis, as they necessitate the use of a digital down-converter unit for both data acquisition and post-processing, limiting user flexibility in analyzing only the desired parts of the signal.
Innovation Solution
A signal post-processing method and circuit that reads a time-and-value-discrete signal, applies a window filter, transforms it into a full-bandwidth frequency-domain signal, and selects a sub-band by setting a virtual center frequency and span, allowing for flexible analysis without altering the resolution bandwidth and frequency range, eliminating the need for a digital down-converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a digital down-converter unit is used for pre-selecting or post-selecting a certain frequency range, then the frequency range selection is achieved, but the device complexity and resource consumption increase significantly
Solution Approach 1:
The patent applies preliminary action by performing frequency range selection during the data acquisition phase using the digital down-converter, so that the frequency selection is already completed before data is stored in memory. This eliminates the need for complex post-processing frequency selection operations.
Solution Approach 2:
The patent creates a virtual frequency span that is a computational copy or representation of the actual frequency data. By setting a virtual center frequency and virtual frequency span, the system can analyze different frequency ranges from the same acquired data without requiring additional hardware or complex processing circuits.
2Adaptability or versatility
If a digital down-converter unit is used for frequency range selection, then the frequency selection is achieved, but the ease of operation is reduced due to complicated calculations
Solution Approach 1:
The patent performs frequency selection calculations during the acquisition phase rather than during post-processing. By pre-selecting the frequency range and storing only the relevant data in memory, the system simplifies subsequent operations to simple data retrieval and display, eliminating complex calculations during analysis.
Solution Approach 2:
The patent changes the operational parameters by using a virtual frequency span that can be adjusted through software without requiring recalculation or reprocessing of the acquired data. The virtual center frequency and virtual frequency span can be modified freely to analyze different frequency ranges from the same data set.
3Productivity
If a predetermined resolution bandwidth and frequency range are fixed during acquisition, then the data is stored efficiently, but the adaptability for analyzing different frequency ranges is lost
Solution Approach 1:
The patent creates a virtual frequency span that is a software-based representation of the frequency data. This virtual copy allows multiple frequency range analyses to be performed on the same acquired data without requiring multiple acquisition passes or modifying the original data, thus maintaining acquisition efficiency while enabling analytical versatility.
Solution Approach 2:
The patent makes the measurement system multi-functional by enabling a single acquired data set to be analyzed across multiple frequency ranges through the virtual frequency span feature. The same acquired data can serve multiple analysis purposes by simply changing the virtual center frequency and span parameters.
Data Source
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AI summary
A signal post-processing method is described, wherein a time-and-value-discrete signal is read from a memory (12) by a signal post-processing circuit (10) wherein a resolution bandwidth and a frequency range of the time-and-value-discrete signal are predetermined. A window filter is applied to the time-and-value-discrete signal. The window filtered time-and-value-discrete signal is transformed to a full-bandwidth frequency-domain signal. A sub-band is selected from the full-bandwidth frequency-domain signal by a selection unit (30) wherein the rest is discarded by the selection unit (30). Further, a signal post-processing circuit (10) as well as an oscilloscope are described.