SU1408321A1 - Broad-line nmr spectrometer - Google Patents

Abstract

This invention relates to nuclear magnetic resonance imaging (NMR) and can be used for research or analysis of materials. The purpose of the invention is to increase the sensitivity and stability of the operation of the NMR spectrum of wide lines with a sensor in the form of an RF 2T bridge, expanding the frequency sweep ranges. The problem is solved by switching to a bridgeless sensorless modulation stabilization system and using an accurate bridge balance mode, which is ensured by using high frequency synchronous detectors and phase shifters in the feedback ring of the bridge stabilization. 1 il.

Description

t1

This is related to nuclear magnetic resonance (NMR) radiospectroscopy and can be used to study or analyze materials.

The purpose of the invention is to increase the sensitivity of the spectrometer, increase the stability of its operation and expand the frequency sweep range.

The drawing shows the block diagram of the intended spectrometer.

The spectrometer contains a source of polarizing field, a high-frequency generator 1, a 2T-BRIDGE sensor 2, a receiver 3, a unit 4 for recording NMR signals and modulating a polarizing field, phase shifters 5 and 6, synchronous detectors 7 and 8 and (JILTER 9 and 10 low Frequency generator 1. High frequency generator 1 is connected to input 2T-bridge 2 and inputs of phase shifters 5 and 6, synchronous detectors 7 and 8 are connected to the outputs of phase voltage 5 and 6, respectively, to outputs of synchronous detectors 7 and 8. unit 4 registration of NMR signals and through the filter The low frequency signals 9 and 10 are respectively connected to the control inputs of the bridge sensor, the signal inputs of the synchronous detectors are connected to the output of the receiver 3, and the input of the receiver is connected to the output of the 2T bridge 2.

For example, 7, a signal proportional to the phase shift offset is selected, and at the output of the second synchronous detector 8, an amplitude shoulder offset. From the outputs of synchronous detectors 7 and 8, signals proportional to the corresponding detuning are fed through filters 9 and 10 of low frequencies to the control inputs of the 2T bridge and compensate for the detuning. The modulation frequency of the polarizing field is selected above the upper cut-off frequencies of the filters 9 and 10 of the low frequencies. This ensures that suppression of the NMR signals by feedback is prevented.

Claims (1)

Invention Formula NMR spectrometer of broad lines, containing a source of polarizing field, a high-frequency generator connected in series, a 2T bridge sensor and a receiver, an NMR signal recording and modulating module for polarizing a field, two phase shifters, two synchronous detectors that differ from aim of increasing the sensitivity of the spectrometer, increasing the stability of its operation and expanding the frequency sweep range by providing a complete balance of the 2T bridge over high frequency The spectrometer works as follows: “It contains two filters. The spectrometer uses the modulation method and the slow passage. The 2T-MOST is fully balanced at a high frequency, and the balance is maintained automatically. Following the orthogonality of the 2T bridge, the signal | 1s of the detuning of the amplitude and phase arm of the bridge are phase shifted by 0. Phase shifts in phase shifters 5 and 6 are set such that at the output of one of the synchronous detectors, 40 45 phase shifters and synchronous detectors are high-frequency, the inputs of synchronous detectors are connected to the output of the receiver, phase shifters are connected between the output of the high-frequency generator and the inputs of the reference voltage of synchronous detectors, the outputs of synchronous detectors are connected to the NMR signal recording unit and through low-pass filters to the inputs control 2T bridge sensor. phase shifters and synchronous detectors are high-frequency, the inputs of synchronous detectors are connected to the output of the receiver, phase shifters are connected between the output of the high-frequency generator and the inputs of the reference voltage of synchronous detectors, the outputs of synchronous detectors are connected to the NMR signal recording unit and through low-pass filters to the inputs control 2T bridge sensor.