NMR Sample Tube Spinning Controller Gate Period Correction
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Solution Overview
Problem
Existing methods for measuring the spinning rate of NMR sample tubes suffer from inaccuracies due to desynchronization between gate periods and pulse sequence signals, leading to measurement errors and reduced responsiveness of feedback control systems.
Innovation Solution
A spinning controller that uses computing means to count pulse signals during gate periods, calculates a corrected gate period by accounting for delay times between signal edges, and generates feedback control signals to synchronize the spinning rate, thereby reducing measurement errors and improving control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the duration of each gate period Tg is prolonged to increase the number of detected pulses, then the measurement accuracy is improved, but the time interval for computation is increased and the responsiveness of feedback control is deteriorated
Solution Approach 1:
The patent changes the parameter of gate period duration dynamically. Instead of using a fixed long gate period, the system uses a short gate period combined with multiple measurements and statistical processing (averaging multiple count values). This allows the system to maintain fast feedback responsiveness while achieving high measurement accuracy through parameter optimization and statistical methods.
2Device complexity
If the gate periods are not synchronized with the pulse sequence signal, then the measurement process is simplified, but time deviations occur and measurement accuracy is deteriorated
Solution Approach 1:
The patent replaces the mechanical/synchronization-based approach with an electronic/software-based correction method. Instead of physically synchronizing gate periods with the pulse sequence signal, the system electronically measures time deviations and applies computational corrections to the count values. This substitution maintains system simplicity while improving measurement accuracy through digital signal processing.
3Ease of operation
If the gate periods are not synchronized with the pulse sequence signal, then the system operation is easier, but local variations in spinning rate cannot be detected and feedback control cannot be provided
Solution Approach 1:
The patent implements a feedback mechanism that uses multiple measurements taken during short gate periods. The system compares successive count values, calculates deviations from the average, and uses this feedback to detect local variations in spinning rate. This enables the system to maintain ease of operation with unsynchronized gate periods while still providing effective feedback control through statistical analysis of measurement variations.
Data Source
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AI summary
There is disclosed a spinning controller which permits the spinning rate of an NMR (nuclear magnetic resonance) sample tube to be measured at improved accuracy and which enables the spinning of the sample tube to be controlled more precisely. The controller has an arithmetic unit (18) and a controller (20). The arithmetic unit (18) establishes gate periods Tg for a pulse sequence signal (110) produced concomitantly with spinning of a sample tube (40) and obtains a count value (Ns) by counting the number of pulses falling within each gate period Tg. Furthermore, the arithmetic unit (18) has functions of finding differences in time from each gate period Tg to the pulse sequence signal (110) occurring around the starting point and ending point of each gate period Tg by making use of a high-speed clock signal (120) and of correcting the duration of the gate period Tg, based on the differences in time. The spinning rate of the sample tube (40) is found based on the duration of the corrected duration of each gate period Tg. The controller (20) controls the spinning of the sample tube (40) such that the spinning rate found by the arithmetic unit (18) agrees with a preset spinning rate.