SU544902A1 - Device for measuring nuclear magnetic resonance spectra parameters - Google Patents

Description

one

The invention relates to the field of radio spectroscopy.

Devices are known for measuring nuclear magnetic resonance (NMR) spectral parameters based on a sweep of the modulation frequency of a polarized magnetic field, in which high accuracy is provided by using highly stable frequency sweep generators, electron-countable frequency meters and nuclear stabilization of resonant conditions according to an internal standard in recording equipment one.

Closer to the invention, the technical solution is a device comprising a frequency sweep generator, a spectra registration unit and a frequency counter.

The resonant frequencies of the lines are determined and after recording the spectrum by sequentially installing the pen of the self-detecting potentiometer of the recording unit on the line and sample slots with an electronic counting frequency meter.

A disadvantage of the known device is that it does not provide a sufficiently high measurement accuracy and requires a considerable amount of time to read the resonant frequency of each line of the spectrum.

The aim of the invention is to improve the accuracy or the corresponding reduction in measurement time.

This goal is achieved by the fact that the device is equipped with a functional converter, a driver of the reference signals, at least two comparison circuits and a complex circuit, while the input of the functional converter is connected to the output of the frequency sweep generator, and the output is connected to the input of the reference driver and the first inputs of the comparison circuit to the second

the inputs of which are connected to the output of the reference signal generator, the outputs of the comparison circuits are connected to the input of the addition circuit, the output of which is connected to the input of the frequency meter, and also, for the sake of simplification,

As a frequency sweep generator, a function generator was used, the output of which is directly connected to the input of the reference frequency driver and the first inputs of the comparison circuits.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - diagrams forming signals in the device.

The device contains a frequency sweep generator 1, a spectra registration unit 2,

a frequency meter 3, a functional converter 4, a driver of the reference signals 5, a comparison circuit 6, 7 and an addition circuit 8. The device operates as follows. The generator 1 is controlled by the sweep voltage from block 2. Variable linearly in

During the period or half-period, the voltage 9 (Fig. 2) from the output of the function transformer is fed to the shaper of the reference signals 5 and simultaneously to the inputs of the comparison circuits 6, 7. At the time of zero crossing of the signal 9, the polarity of the output signals 10, 11 of the shaper 5 changes The output voltages 12, 13 of the comparison circuits 6, 7 change their values at the instants of coincidence of the signal 9 with the reference signals 10, 11, respectively. At the output of the addition circuit, signals 14 are formed, the temporal position of which is determined by the moments of the change in output voltages 12, 13. These signals are delivered to the input of the frequency meter.

As a generator of the frequency sweep, it is advisable to use a functional generator that generates a voltage that varies linearly with time. In this case, there is no need to use a functional converter and the output of the generator 1 is directly connected to the input of the reference signal generator 5 and the first inputs of the comparison circuits 6, 7. As a result, the device is simplified.

An increase in the accuracy of measurements or a corresponding reduction in the measurement time is determined by repeated repetition of periodic signals during the period of the voltage sweep of the frequency sweep generator, which enters the input of the frequency meter.

For example, during the formation of 10 pulses during a generator period of 1, the main component of the measurement error is reduced by a factor of 10 due to the sampling rate of the frequency meter or the counting time is reduced by the same amount.

Formula 1 3 about b ete n and

1. A device for measuring parameters of nuclear magnetic resonance spectra, comprising a frequency sweep generator, a unit for detecting siectors, and a frequency meter, differing from the fact that, in order to increase accuracy or reduce measurement time, it is equipped with a functional converter, a driver of oior signals, at least two by comparison circuits with the addition circuit, wherein the input of the functional converter is connected to the output of the frequency sweep generator, and the output is connected to the input of the reference frequency driver in and the first inputs of circuits, to the second inputs of which

the output of the reference signal generator, the outputs of the comparison circuits are connected to the input of the addition circuit, the output of which is connected to the input of the frequency meter. 2. The device according to claim 1, characterized by

In order to simplify, a function generator was used as a frequency sweep generator, the output of which is directly connected to the input of the driver and the first signals

comparison circuits.

Sources of information taken into account in the examination:

1.Avt. St. JMb 394712, Cl. G 01N 27/78, 1973.

2. Avt. St. No. 396616, cl. G 01N 27/78, 1973 (irototi).

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