Variable Bandwidth Frequency Mask Trigger for Spectral Analysis
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Solution Overview
Problem
Current test and measurement instruments are limited in triggering on spectral events in systems with varying bandwidths, leading to measurement errors and missed data due to their inability to process non-equally spaced filters, especially in spectral emission masks that require analysis across different bandwidths.
Innovation Solution
A frequency mask trigger system capable of operating with variable bandwidths, processing all acquisition samples in real-time to detect violations across specified bandwidths, allowing for seamless data storage and analysis without losing information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If swept spectrum analyzers measure SEM in narrow resolution bandwidth, then measurement precision is improved, but transients and impulse noise are reduced in amplitude causing measurement error
Solution Approach 1:
The system dynamically adjusts the resolution bandwidth of FFT bins based on the spectral emission mask requirements. Different frequency ranges can have different bandwidths, allowing the system to optimize between transient detection and spectral precision for each segment of the spectrum being measured.
Solution Approach 2:
The frequency spectrum is divided into multiple bins with different bandwidths. Each bin can be configured with appropriate bandwidth for its specific frequency range, allowing simultaneous optimization for both transient detection and spectral measurement precision across different parts of the spectrum.
2Measurement precision
If swept spectrum analyzers sweep the entire band in single narrow RBW, then spectral precision is improved, but measurement time increases and transients may be missed
Solution Approach 1:
The system uses dynamic bandwidth adjustment where the RBW of each FFT bin is configured according to the specific requirements of that frequency segment. This allows the analyzer to process the entire band simultaneously with optimized bandwidths rather than sweeping sequentially, dramatically reducing measurement time while maintaining precision.
3Device complexity
If present triggers operate only with equally spaced filters, then device complexity is reduced, but adaptability to varying bandwidth systems is limited
Solution Approach 1:
The trigger system allows different bandwidth characteristics for different frequency bins. Each bin can have its own bandwidth configuration, enabling the system to adapt to varying bandwidth requirements across the spectrum while maintaining a unified trigger framework.
Solution Approach 2:
The FFT-based trigger system can handle both equally spaced and non-equally spaced frequency bins within the same framework. This universal approach allows the system to adapt to different spectral emission mask requirements and bandwidth configurations without requiring separate trigger systems.
Data Source
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AI summary
Disclosed is a test and measurement instrument (200) having a multiple variable bandwidth frequency mask. The instrument includes an input processor (205, 210, 220) for receiving an input signal and producing a digital signal, as well as a trigger signal generator (260, 262) for generating a trigger signal on the occurrence of a trigger event. A time to frequency converter (250, 252) converts a frame of digital data from the digital signal into a frequency spectrum having at least two frequency bins of dissimilar frequency widths. Each frequency bin has a power amplitude value. The trigger signal is generated when the power amplitude value of any of the at least two frequency bins violates an associated reference power level. In some cases the output may be shown as a density trace, and the trigger signal generated when any point of the density trace violates an associated density threshold.