SU676941A1 - Radio signal spectrum analysis method - Google Patents

Description

neonfrequency modulated. In order to obtain spin echoes from cliques, compressed in time from each component of the signal under study, ferromagnetic materials enriched with isotopes, for example, Q, Ivln, whose cores have half-integral spin and are in strong internal magnetic aole ferrochmagnet.

At the time t to, the first auxiliary pulse, is supplied, for which a delta pulse is chosen to create an inverse population of energy nuclear levels (cooking the vector of the core field of magnetization by 90 °) and uniformly excite the Bicex spies, and then the transformed transformed signal. In this case, the convertible signal under study is a multi-frequency pulse, the spectral component of which is modulated on a frequency. The frequency deviation in the transformed signal should not exceed the frequency band of the Larmor-glaze, but should not be less than the width of the spectrum of the signal under study. The duration of the signal under study should not exceed the time of the phase memory of the working substance (spin-spin relaxation time). To obtain spin echo sigals from each spectral component of the subsequent signal, a second auxiliary pulse with linear frequency modulation is applied to the working substance at the time point I2, the rate of the filling frequency being equal in it to be equal to the rate of change of the filling frequency in the transformed signal under study, but opposite to her by the sign} -. The frequency deviation in the second auxiliary impulse is located above the Lumor frequency band of the working substance, which for the specified working substances reaches ten MHz. Failure to comply with this condition can lead to a worse resolution of the analyzer and to the destruction of the spin echo sipnal.

The resulting spin echo responses are C0: the battle is compressed with the time-frequency-modulated spectral components with amplitudes proportional to the amplitudes of the spectral components of the examined sypnal. The distance in time between the compressed echo responses received is proportional to the frequency interval between the respective spectral components. The presence of a ferromagnet's own internal field makes it possible to analyze the spectra of radio pulses without an external permanent inhomogeneous magnetic field.

In this way, it is possible to analyze the spectra of radio pulses, the frequency of which does not exceed the value of / sTi,

where T is the time of the spin-lattice relaxation of the working substance. Distance in time

2,

between echo response mi equals / where

 -g.h

Aso is the frequency interval between the corresponding frequency components, and -trm is the duration of the second auxiliary pulse. The duration of the echo response is V2Acoj, therefore allowing

ability a / v for signals of the same

Level equals A / B: g

To reproduce signal spectra without distortion, a duration is necessary.

the second auxiliary impulse to choose less time phase memory of the working substance.

A device that implements the long-distance method consists of nz serially connected amplifier /, mixer 2 and intermediate frequency amplifier 3 connected to the radio frequency coil 4 with working medium 5, the delay line 6 connected in series and the generator 7, whose output is also connected to the radio frequency coil 4, are serially connected modulator 8, delay line 9, generator 10 and amplifier U /, the output of which is connected to the radio frequency coil 4, second output

generator W is connected to the input of the generator 12, which performs the sweep of the oscilloscope 13. The third output of the generator 12 through the generator 14 is connected to the input of the amplifier 15, two outputs of which are connected to other plates of the oscilloscope 13, and the third - to the radio remote control 4. Second output module torus 8 through the local oscillator 16 is connected to the second input of the mixer 2.

The operation of this device is as follows. The signal under study through the amplifier / is fed to the mixer 2, where the impulse with a linear in time modulation of frequency arrives from the LO 16

filling. The intermediate frequency signal through amplifier 3 sweeps the frequency to the RF coil 4, which is wound on the working substance 5. The test signal is fed to the delay line 6 to start the generator 7 of the first auxiliary pulse, from the output of which the pulse is fed to the RF coil 4. Besides In addition, the signal under study is fed to the modulator 8 to start the local oscillator 16. The modulator 8 through the delay line 9 starts the generator 10 of the second auxiliary pulse.

From the output of the generator 10, the second auxiliary impulse goes through the amplifier // to the radio frequency coil 4, and the induced echo responses through the amplifier 15 are fed to an oscillo | Lraf 13. An oscilloscope sweep 13 is started from the transmitter.

Claims (1)

12 after the end of the second auxiliary impulse. At the same time, the strobe pulses from the output of the generator 14 are opened by the amplifier 15 for the sweep time. The device analyzes the spectrum of the second incoming pulse, as the first incoming pulse is needed to start the generator 7 of the first auxiliary pulse. The invention of the method of analyzing the radio signal spectrum, which is again on the use of spin echo and converting the input signal into radio pulses with linear modulation of the filling frequency, is characterized in that, in order to increase the frequency of the analyzed frequencies and simplify the method, IB as the first auxiliary pulse acting on the working substance, use the delta. pulse, and as the second auxiliary impulse arriving at the working substance after the input transformed signal, use form a pulse rate of change of frequency which the filling rate of change of frequency of the input signal converted filling, but invertible and in sign.