Mass Spectrometer Digital Step Attenuator Dynamic Range
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Solution Overview
Problem
Conventional Analogue to Digital Converter detection systems in mass and/or ion mobility spectrometers suffer from a relatively limited dynamic range, which can lead to signal saturation and reduced resolution in data acquisition.
Innovation Solution
Implementing a programmable attenuator or amplifier, such as a high-speed digital step attenuator or variable gain amplifier, to adjust the signal intensity before digitization, ensuring it does not exceed the dynamic range of the digitization device by switching the attenuation or gain factor during data acquisition, and combining data sets acquired at different attenuation factors to form a composite data set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Analogue to Digital Converter detection system is used, then the system structure is simple, but the dynamic range is limited and signal saturation occurs
Solution Approach 1:
The patent implements a programmable attenuator that can dynamically adjust its attenuation factor during data acquisition. This allows the system to adapt to varying signal intensities in real-time, extending the effective dynamic range by preventing saturation for strong signals while maintaining sensitivity for weak signals, thus resolving the contradiction between limited dynamic range and system simplicity.
Solution Approach 2:
The patent changes the attenuation parameter of the programmable attenuator during operation to match the dynamic range requirements of the digitizer. By switching between different attenuation factors based on signal intensity, the system effectively expands its measurable range without requiring multiple digitizers or complex hardware changes.
2Measurement precision
If signal intensity is increased to improve detection sensitivity, then detection sensitivity improves, but signal saturation occurs exceeding the dynamic range of the digitization device
Solution Approach 1:
The programmable attenuator dynamically adjusts attenuation levels during data acquisition based on the detected signal intensity. When strong signals are detected, the attenuator increases attenuation to prevent saturation; when weak signals are present, it reduces attenuation to maintain detection sensitivity. This dynamic adaptation resolves the contradiction between detection sensitivity and signal saturation.
Solution Approach 2:
The system employs feedback control where the attenuator's attenuation factor is adjusted based on real-time monitoring of signal intensity. This feedback mechanism ensures that the signal remains within the optimal dynamic range of the digitizer, preventing saturation while maintaining maximum detection sensitivity across varying signal conditions.
3Reliability
If attenuation factor is switched during data acquisition, then dynamic range is extended, but signal propagation delay varies
Solution Approach 1:
The system performs preliminary calibration to characterize the signal propagation delay as a function of the attenuator's attenuation factor. This pre-established relationship is stored and used during data acquisition to correct for delay variations, allowing the system to switch attenuation factors dynamically while maintaining accurate time-of-flight measurements.
Solution Approach 2:
The system measures the actual signal propagation delay for each attenuation factor setting and uses this feedback information to correct time-of-flight measurements. By compensating for the delay variations introduced by attenuator switching, the system maintains high time-of-flight resolution while benefiting from the extended dynamic range.
Data Source
AI summary
A method is disclosed comprising passing a signal output from a detector through a programmable attenuator or a programmable amplifier prior to digitizing the signal, and switching an attenuation factor or gain factor of the programmable attenuator or the programmable amplifier one or more times during a data acquisition period.