UA9235U - Method for measuring intensity of low-power radio radiation - Google Patents

Abstract

The proposed method for measuring intensity of low-power radio radiation consists in receiving the monitored radio radiation by an antenna and a receiver, which transforms the output signal of the antenna into a direct voltage signal, measuring the output signal (U1) of the receiver, reducing the radio radiation by a translucent screen with a transmission factor of 0.4 à 0.6, measuring the output signal (U2) of the receiver that corresponds to the reduced radio radiation, summing the radio radiation at the input of the antenna with the reference noise signal, measuring the output signal (U3) of the receiver, and determining the intensity () of the received radio radiation by the following equation: where is the dispersion of the noise signal at the input of the antenna.

Description

Description of the invention

The useful model refers to radio measuring equipment and can be used to measure 2 the intensity of radio radiation of objects of different physical nature.

All living and non-living objects emit radio waves in a wide frequency range. However, the level of radio radiation is very small compared to optical radiation. Even in the ultra-high frequency (UHF) range, the intensity of radio radiation (10,777...10,715 W/cm7) is often less than the intensity of the inherent noise of the receiving equipment, which causes large errors in the estimation of the intensity of received radio radiation.

For a known method of measuring weak radio emissions, see Yu.O. Skrypnyk, V.P. Manoilov, O.P. Yanenko.

Modulating radiometric devices and systems of NVU range. - Zhytomyr: ZHITI, 2001, -P.194-1981), which consists in the fact that the investigated radio radiation is received by an antenna, the output signal of the antenna is converted into a constant voltage by a radiometric receiver, the input signal of the receiver is compared with the reference noise, the equality of the compared signals is established at zero value of the constant voltage at the output t of the radiometric receiver, the intensity of the reference noise is measured, by which the intensity of the received radio radiation is determined.

However, when performing the comparison operation, it is not possible to exclude from the result the noise of the antenna and the switching interference of the switch of the antenna and the equivalent load, which reduces the accuracy of the measurement of the intensity of the received radio radiation. A significant error is introduced by the operation of establishing the equality of the compared signals, which requires ensuring the discreteness of the reference in the reference noise chain at the level of the fluctuation threshold of the sensitivity of the radiometric receiver.

A method of measuring weak radio emissions is also known | see patent of Ukraine Mo70229A, IPC 501513/00, Byul. Mo9, 2004|, which consists in the fact that the investigated radio radiation is received by an antenna, the output signal of the antenna is converted into a constant voltage by a radiometric receiver, its value is measured at 29 °C, the investigated radio radiation is weakened by passing it through a screen, and the reduced - voltage "SHO" is measured at the output radiometric receiver, add standard noise to the radio radiation received by the antenna, measure the increased voltage Oz at the output of the radiometric receiver and determine the received radio radiation.

In addition, the known method includes the operation of eliminating the attenuation of the received radio radiation after o 3o of the second measurement and adding to the radio radiation received by the antenna the reference noise, which determines the result of the third measurement, and the dispersion of the received radio radiation Pe is determined by the formula: сч зр де Ш.4, 0» and Oz - voltages at the output of the radiometric receiver; tsg - dispersion of reference noise; « p is the calibrated transmission coefficient of the radio-transparent plate. 8

However, the result of the operation of weakening the investigated radio radiation by passing it through a 50 screen depends on many factors (temperature, humidity, surface cleanliness, degree of contamination, etc.). c As a result, the accuracy of the known method of measuring weak radio emissions is low.

From" The useful model is based on the task of creating such a method of measuring weak radio emissions, in which, by introducing new operations, it is ensured that the influence of the variability of the transmission coefficient of the radio-transparent plate on the measurement result is excluded, which will ensure high accuracy of the measurement of weak radio emissions. The problem is solved by the fact that in the method of measuring weak radio emissions, which consists in the fact that the investigated radio radiation is received by an antenna, the output signal of the antenna is converted into a constant voltage by a radiometric receiver, its value I 5 is measured, the investigated radio radiation is weakened by passing it through a screen, measure the reduced voltage OO o" at the output of sl 20 of the radiometric receiver, add reference noise to the radio radiation received by the antenna, measure the increased voltage Oz at the output of the radiometric receiver, and determine the received radio radiation, according to a useful model, the screen is used semi-transparent with a transmission coefficient of radio radiation equal to 0, 6...0.4 and additionally passed through the antenna to the translucent reference screen

Sozv noise, and the received radio radiation is determined by the formula:

Oz Z where it is the dispersion of the reference noise introduced into the antenna. Introduction of operations to weaken the received radiation by a translucent screen with a transmission coefficient of 0.6...0.4 (the reflection coefficient of the screen is 0.4...0.6), directing the reference noise directly into the antenna and radiating it through the translucent the screen, received by the antenna together with the weakened test radio radiation of the reference noise reflected from the semi-transparent screen, allows you to calculate the dispersion of the radio radiation under study, taking into account the dispersion of the reference noise, based on the three values of the output voltage of the radiometric receiver, which correspond to the indicated b5 operations. At the same time, the variability of the transmission coefficient and the reflection coefficient of the translucent screen do not affect the measurement result, which ensures high accuracy of the measurement of weak radio emissions.

The essence of the useful model is explained by the figure, which shows the functional scheme of the device for implementing the proposed method of measuring weak radio emissions.

The device contains an antenna 1, to the output of which a three-arm circulator 2 is connected to a radiometric receiver 3, the output of which is connected through an analog-to-digital converter (ADC) 4 to the input of the microcomputer 5. A digital indicator b is connected to the first output of the microcomputer 5, and a digital indicator b is connected to the second output digital-to-analog converter (DAC) 7, the output of which is connected to the executive mechanism 8, which is connected to the movable translucent screen 9. The reference noise generator 10 is connected to the input of the variable /o attenuator 11, the control input of which is connected to the output of the DAC 12 , the input of which is connected to the third output of microohm 5. The output of variable attenuator 11 is connected to the second input of circulator 2.

The device works according to the program recorded in the memory of micro-EEOM 5. The program provides the performance of the main and two additional measurements in accordance with the proposed method and computational processing of the results of all measurements.

The method of measuring weak radio emissions is carried out in the following sequence. Radio radiation from the object under investigation is received by antenna 1. In most cases, the received signal has a noise-like character, low power and is indistinguishable against the background of the antenna's own noise. Given that the received signal and the inherent noise of the antenna are uncorrelated, the variance of the output total signal can be represented as the sum of variances: 7 2 Apoap? (0) pd Ox Od where n is the dispersion of the antenna output signal;

Ptn - dispersion of received radio radiation; -

Pet is the dispersion of the inherent noise of the antenna.

The signal from antenna 1 passes through the arms A-B of circulator 2 and enters the input of the radiometric receiver

With having a linear transformation function with respect to the power (dispersion) of the input signal. In the process of operation of I c) radiometric receiver, due to the instability of its parameters and the variability of the level of inherent noise from the conversion units, the conversion function (static characteristic) changes its slope and shifts relative to the zero value. So, for example, a decrease in the gain of the receiver leads to a decrease in the steepness of the static characteristic, i.e., a decrease in its sensitivity, and an increase in inherent noise causes a shift in b» zero. Therefore, the output voltage of the receiver ). taking into account its errors, it can be represented in the form - t orp2 zp 2

She Oh On Audrey « where 5 is the nominal steepness of the characteristic of the radiometric receiver; - t- АВИ/8 - relative sensitivity error (multiplicative error); ; и и - с Пи - dispersion of inherent noises of the radiometric receiver; "» A is the absolute error of the radiometric receiver from zero shift (additive error). p . . . -

The output voltage of the radiometric receiver Z is converted into a code using the analog-to-digital converter 4 and entered into the memory of the micro-ohm 5. This completes the first measurement cycle.

In the second cycle, the entrance of the antenna 1 is closed by a translucent screen 9, which moves from the position | in ее, the position of ІІ by the executive mechanism 8. The command to move the screen 9 is issued by the microcomputer 5 with the help of a digital-to-analog converter 7. The translucent screen 9 has a transmission coefficient approximately equal to its reflection coefficient. As a result of the weakening of the received radio radiation introduced by the screen, the output voltage of the radiometric receiver decreases to the value of sl - by vp? vp Kk)

Пе е БЙ я оо Оу оз) where 2 is the coefficient of transmission of the screen in terms of power.

ОСо55 The reduced value of the О2 voltage is converted into a code by the analog-to-digital converter 4 and entered into the memory of the microohm 5.

In the third cycle, at the command of the micro-OEEOM 5, a signal that opens the variable attenuator 11 is sent to the variable attenuator 11 through the DAC 12. As a result, a noise signal from the reference noise generator 10 is sent to the input C of the circulator 2, which is sent to the input of the antenna through the C-A shoulder 1. The reference noise signal vo is emitted by the antenna 1 through the translucent screen 9. The partially reflected signal from the screen is again received by the antenna 1 and through the A-B shoulder of the circulator enters the input of the radiometric receiver 3. As a result of summing the reflected noise signal with the weakened received radio radiation at the output of the radiometric of the receiver Z we obtain the increased voltage 65 from "BI ЖrОх оз Од Од where g is the power reflection coefficient (according to the terminology adopted in microwave technology, GE

Г - reflection coefficient).

The voltage Oz is converted by an analog-to-digital converter into a code that is entered into the memory of microeOM 5. 2 Based on the results of measurements in the first and second cycles in microeOM 5, the first difference is calculated - 2 (5

M-va hui -vyu OS 76 According to the results of the third and second measurement cycles, the second difference is calculated: tsa - 05 - В Ua (0

Given the fact that for a semi-transparent screen 9, the ratio reg 1 (7) is valid

We obtain g-1- in (8)

Next, the ratio of the first (5) and second (6) differences is calculated, taking into account the ratio (8) to 82

Shi70» S1stya Oh o

Ia - It's IY it's pe -

From the expression (9), the final result of the measurement is obtained: n - 75 i: (o) o

Oz 7 (ze)

It can be seen from formula (10) that the result of the calculations does not depend not only on the multiplicative and additive components of the error (the radiometric receiver, but also on the variability of the radiophysical parameters of the semi-transparent screen (the transmission coefficient p and the reflection coefficient r). This allows us to ensure high accuracy of measurement of weak radio emissions with reduced requirements for the stability of geometric dimensions and electrophysical properties of the screen material.

Studies have shown that the relative error of determining the dispersion of the investigated radio radiation does not exceed 0.595 when changing by 10...1595 and the transmission coefficient of the radio ceramic screen under the influence of temperature and other factors

Claims (1)

Formula of the invention and? The method of measuring weak radio radiation, which consists in the fact that the investigated radio radiation is received by an antenna, the output signal of the antenna is converted by a radiometric receiver into ee, a constant voltage, its value is measured )/, the investigated radio radiation is weakened by passing it through a screen, the reduced voltage o at the output is measured radiometric receiver, reference noise is added to the radio radiation received by the antenna, the increased voltage Oz at the output of the radiometric receiver is measured and the received radio radiation is determined, which differs in that a semi-transparent screen with a radio transmission coefficient of 0.6-0.4 is used c 20, it is additionally passed through the antenna to the translucent screen is the reference noise, and the received radio radiation w is determined by the formula: 60 b5