SU475884A1 - Impulse spectrometer of nuclear quadrupole resonance - Google Patents

Abstract

PULSE qnEKTPOMETP nuclear quadrupole resonance, the pulse generator .soderzhaschy high 'Coy frequency of the exciting coil, electromechanically conjugated receiving device and a local oscillator, blokavtomaticheskoy tuning oscillator device and multi-program adjustment drive, about .T - lichayuschiys in that, in order to increase sensitivity and frequency resolution of the spectrometer, it is equipped with a multichannel filter connected to the output of the receiving device, each channel of which is equipped with a cell ativnost memory circuit synchronous switching input filter circuit channels and serial interrogation of cells and RAM memory synchronous transferred; channels exception accumulator.

Description

(Ls

H

and

IA

"

st (sp

00 00

The invention relates to the field of radio spectroscopy and can be used for physico-chemical studies of a solid by the method of nuclear resonance. A pulsed spectrometer of nuclear quadrupole resonance is known, in order to simulate the sample search and study time, all RF blocks of the spectrometer-generator, the local oscillator and the receiver are quickly rebuilt using an executive mechanism controlled by a software device, and the difference between adjacent ones is often It is chosen so that it is of the order of the width of the spectrum of probe pulses. The disadvantage of such a radio spectrometer is low sensitivity and resolution due to the fact that the width of the signal spectrum is already the width of the receiving channel. The aim of the invention is to increase the sensitivity and frequency resolution of the spectrometer. For this, the proposed spectrometer is equipped with a multichannel filter connected to the output of the receiving device, each channel of which is equipped with a memory cell, a synchronous switching circuit for the filter channel inputs and a sequential polling circuit for the memory cells and synchronous switching of storage channels. The drawing is a block diagram of the proposed spectrometer. It consists of a generator of 1 pulses, a receiver 2, a local oscillator 3, a block 4, a loop coil 5, a sample under study b, a multichannel cable pit 7, a software device 8 of the executive mechanism 9, a t-channel frequency block 10, a block 11 RAM and the scanner polling circuit 12. The pulsed nuclear resonance spectrometer works as follows. The test sample b, placed in the contour coil 5 of the generator of the 1 HF pulses, is affected by powerful probe pulses. The frequency of the generator 1 is quickly and according to the program defined by block 8, tuned by the actuator 9 with simultaneous tuning of the frequency of the receiver 2 and the local oscillator 3. Sipnals of nuclear induction and spin ech induced in the loop coil 5 together with noises are amplified by the pulse receiver 2. the signals received in the common channel with band 4 f) at intermediate frequency f ,, are fed to the input of the ha-channel frequency block 10, in which the frequency separation of the signals is made using filters with a leak band. Dff. From the output of each analysis channel after amplitude detection, signals are simultaneously fed to m cells of the RAM 11. The storage of signals in all cells occurs at the moment when the maximum amplitude value is reached - induction or echo signals, which are defined in the software device 8 and fed into the circuit 12 for generating gates for block 11. Signals are stored in memory until these cells 12 sequentially from the first to the t-th cell with simultaneous switching of the channels of the accumulator 7, the interrogation of all the memory cells occurs in a time shorter than the period of the probe pulses, i.e. the use of a multichannel frequency block does not increase the time of passage of the frequency subband. Since the total number of reception channels of the spectrometer N and each reception channel is divided into m narrow analysis channels with an lff band each, the total number of channels of the spectrometer and multichannel storage device is equal to N t. Thus, the instrument allows in the speed search mode to receive a signal with by the band LL L / t, which increases the power sensitivity of the spectrometer by m times and its frequency and resolution by the same number of times.

Claims (1)

PULSED NUCLEAR QUADRUPOLE RESONANCE SPECTROMETER, containing a high-frequency pulse generator with an exciting coil, an electromechanically coupled receiving device and a local oscillator, a local oscillator automatic tuning unit, a program tuning device and a multichannel storage device that differ in frequency and sensitivity to increase the resolution spectrometer, it is equipped with a multi-channel filter connected to the output of the receiving device, each of whose channels is equipped with a cell perativnoy memory circuit synchronous switching input filter circuit channels and serial interrogation of RAM cells and synchronous _re; switching channels of the drive.