SU796775A1 - Device for automatic measuring of noise factor - Google Patents

Description

(54) DEVICE FOR AUTOMATIC HUMERING OF THE NOISE RATIO

one

The invention relates to radio engineering and can be used in instruments for measuring noise figure with an extended range of magnitude of the measured signals.

A device containing an adjustable noise generator, a switchable attenuator, a selective amplifier, an integrating comparison circuit, a gain-controlled amplifier, a switch, an integrating circuit, an electronic key, a storage element, a three-position relay element, a control device, a digital reading device, a software block 1 are known. .

A disadvantage of this device is the large measurement error in the presence of small noise signals. The error arises from the fact that the measurement of the noise figure is carried out with a constant noise generator.

The closest in technical essence to the present invention is a device for measuring the coefficient, noise, containing a source of noise, the output of which through the quadrangular under study is median with a low power meter. Output last

separately connected to the inputs of the electronic key and the ratio meter, the second input of which is connected to the electronic key. Manager

the input of the latter is connected to the output of the noise source. The output of the ratio meter is connected to one of the inputs of the adder, the other its input is connected to the input block of calibration numbers.

The output of the adder is connected to the indicator 2.

The disadvantage of this device is the narrow dynamic range of input signals and low accuracy

measurements in the presence of a small power meter at the input of a weak or too large signal.

The purpose of the invention is to expand the dynamic range of the output signals and increase the accuracy of measurements. The goal is achieved by the fact that a voltage divider and an analog-to-digital converter and a microprocessor are connected in series to a device for automatically measuring the noise figure, containing a noise source, a small power meter and a key, as well as an indicator, and a microprocessor

input divider nDRUCHYM INPUT (- / JCT

It is connected to the input of the key of small mono components, .OD co-hops is connected to the input of the key, the output of which is connected to the input of the analogue-digital converter, and the outputs of the I-JUIKPOprocessor are connected to the control inputs of the noise source, voltage divider and key, and with indicator.

The drawing shows the functional diagram of the device for the automatic measurement of the noise figure.

A device for automatically measuring the noise figure contains a noise source 1, the output of which is connected to a series-connected voltage divider 3, a low power meter 4, an electronic key 5, an analog-to-digital converter 6, a microprocessor 7 and a microprocessor 7 through the four-port circuit under study 2. 7 are separately connected to the control via the inputs of the electronic key 5, the voltage divider 3 and the noise source 1.

The device works as follows. The signal from noise source 1 arrives at the quadrupole 2 under test. From the output of the quadrupole 2 under study, noise arrives at the voltage divider 3, which is at that time in an arbitrary division stage. The code for the voltage divider 3 is stored in the memory of the microprocessor 7. The signal from the voltage divider 3 is fed to the meter 4 low power, p. the output of which is removed is the noise voltage. This voltage is fed through an electronic switch 5 to an analog-to-digital converter 6, where the signal is converted into a digital code and fed to a processing unit in microprocessor 7, where the transfer factor of the voltage divider 3 is also taken into account and the resulting temperature is calculated. In the event that this error is exceeded from the preset limit, microprocessor 7 issues a control command to divider 3 voltage for 1 switching its steps from the circuit.;:::; ;; about obtaining noise figure with the required error. Automatic calibration of the device takes place with the help of the power outage bw.gochkika 1 noise by microprocessor 7,. The magnitude of the noise coefficient, of the access with desired accuracy; Indicator 8. The voltage divider 3 has steps with a division factor of less than one for an input signal too large and a larger one for a signal that is too small.

The positive effect is achieved due to the fact that there is an operational control of the steps of the voltage divider 3 using a microprocessor.

Claims (2)

1. USSR author's certificate No. 306426, G 01 R 27/28, 1974. 2. USSR author's certificate No. 457940, G 01 R 29/00, 1975.