GB 12201-1990 Test method for standing wave coefficient of marine navigation radar wave feed system
Some standard content:
UDC621.396.965:629.12.018
National Standard of the People's Republic of China
GB12201—90
Test methods of VswR of the waveguidefeed-system for marine radarPublished on 1990-02-01
State Administration of Technical Supervision
Implementation on 1990-08-01
W.National Standard of the People's Republic of China
Test methods of VswR of the waveguidefeed-system for marine radarSubject content and scope of application
GB 12201.--90
This standard specifies the test method for the voltage standing wave coefficient of the waveguide feed system (hereinafter referred to as the waveguide system) of ship navigation radar. This standard is applicable to the inspection of the voltage standing wave coefficient of the guided system of ship navigation radar. 2 Reference standards
·GB2421 General rules for basic environmental testing procedures for electrical and electronic products 3 Terms and symbols
3.1 Voltage standing wave coefficient S
The ratio of the maximum value EB and the minimum value B of the standing electric field in the waveguide transmission line, Lang: S
3. 2 Voltage reflection coefficient p
The ratio of the reflected wave electric field intensity at any point in the waveguide transmission line to the incident wave electric field intensity +, that is: The modulus of the voltage reflection coefficient |β| and the voltage standing wave coefficient s have the following relationship: o
3.3 Return loss L
Under the condition of matching the signal source. The decibel number of the power reflected by the load in the transmission system is reduced relative to the incident power or relative to the total reflected power, that is
Te =— 20 lglol
The return loss Le and the voltage standing wave coefficient S have the following relationship: Tm =- 20 18 %
Approved by the State Administration of Technical Supervision on February 1, 1990. (4)
Implemented on August 1, 1990
W.4 Test Principle
4.1 Test Line
GB 12201---90
According to the definition of voltage reflection coefficient, the maximum value H… and the minimum value E_ of the standing wave electric field are measured by the test line, and the voltage standing wave coefficient of the measured waveguide system at the terminal of the test line can be determined: 4.2 Reflectometer Ratio Meter Method
According to the definition of voltage reflection coefficient, the paired directional couplers in the reflectometer are used to couple out a certain ratio of incident wave power and reflected wave power respectively. And through its "paired detector detection, it is transformed into a video signal and then sent to the ratiometer for comparison, so as to determine the electrical reflection coefficient of the waveguide system under test. The output of the ratiometer is added to the axis of the recorder or oscilloscope, and a sweep frequency curve of the reflection coefficient of the waveguide system under test relative to the frequency can be obtained.
This instrument is suitable for the case where the crystal of the device is subjected to square law detection. 4.3 Sweep frequency reflection attenuation substitution method
According to the definition of return loss, a directional coupler in the reflectometer is used to couple out part of the incident wave power, and after detection by the detector, it is locked to the gate of the sweep frequency signal source to stabilize the sweep frequency signal source. Output (that is, maintain the uniform loss of the incident wave unchanged). In the coupling branch of the Dan Bay coupling reflected wave power extension coupler, a microwave standard attenuator is connected, and a short-circuit device is connected to the reflectometer end. Corresponding to the different attenuation values of the standard attenuator, a family of return loss calibration curves can be drawn. Then, the synchronous loss sweep curve of the measured reading guide system is compared with the return loss calibration curve to determine the return loss of the measured waveguide coefficient. This method is not affected by the detection characteristics of the product, nor does it require the coupling degree of the two directional coupling groups to be consistent. A standard attenuator is used. 5 Test instruments and equipment and their requirements 5.1 Microwave signal source The input power is less than 5mW; The spectrum amplitude is less than -34 dB (if it cannot be reached, a filter can be connected in series to meet this requirement) h,
Power stability is not less than 0. 07 dB/6 min; frequency stability is not less than ≤×10-1/16 mid
1000Hz modulated frequency stability is not less than 0.7×108/5min5.2 signal source
Output power is not less than 6 mw;
harmonic amplitude is less than: 34dB (if it cannot be achieved, a filter can be connected in series to meet this requirement); b
output frequency response is not greater than +51B when not excited; c
doutput frequency response is not greater than ±51dB when externally stabilized, 5.3 Baseline measurement
The synthetic standing wave coefficient of the measuring line is not greater than 1.03.5.4 Line wave body measurement
a. Small signal test wave sensitivity 200V/iW; h. With a visible test line to be calibrated.
5.5 Standing wave indicator
1. Nonlinear error is not more than 2%;
b. Gain stability is not less than 0. 07 dB/5 min. 5.6 The standing wave coefficient of the four-matched load is not higher than 1.02.
W.5.7 The squareness of the directional coupler is not less than 40dB;
The coupling degree is about 10;
The standing wave coefficient of the main line is less than 1.1:
GB 12201--90
Coupling frequency response: The swept frequency reflectometer ratiometer method is used, and the coupling frequency response deviation of the two paired directional couplers is required to be not larger than ±0.5h.
5.8 Crystal detector
a. Small signal detection sensitivity is about 100uv/uw; b. Detection sensitivity frequency response: using the swept reflectometer ratiometer method, the difference in the sensitivity frequency response of the two paired detectors is required to be no less than 0.7 dB:
c. The detection characteristics of the working area deviate from the square law error; using the swept frequency reflectometer method, the error is required to be less than 0.3, d, the standing wave coefficient is not greater than 1.5,
5.9 Ratiometer
The calibration error of the logarithmic subtraction ratiometer is not greater than 0.5 dB; a.
h The calibration error of the tangent source ratiometer is not greater than 2.5%. 5.10 Movable short circuit
The standing wave system is not less than 100.
5. 11 Standard attenuator
Calibration error less than 2%
b. The corresponding stationary coefficient is not greater than 1.22
6 Test conditions
The test should be carried out under the normal test atmosphere conditions specified in GB242. 7 Test sample
The waveguide system refers to the combined system of various waveguide components connected between the output port of the transceiver and the input port of the antenna. During the test, the various types of waveguides in the waveguide system should be connected in the specified order and requirements in accordance with the provisions of the product standard to form the waveguide system under test.
8 Test procedure
8.1 Measurement line method
8.1.1/Test block diagram
The test block diagram is shown in Figure 1. bzxz.net
W board is simulated number surface
8.1.2 Test steps
Hu re-ticket
discrete
GB 12201 90
and set indicator
Figure 1 Block diagram of measurement line method
8.1.2.1 Before testing, the detection crystal needs to be calibrated and the crystal calibration curve is made. 8.1.2.2 Connect the test system according to the figure and adjust the equipment to make it work normally. The dynamic
short circuit
the measured and conducted system
matches the negative number
8.1.2.3 Adjust the signal source to the specified center frequency point, carefully tune the tuning mechanism of the measurement line probe, and adjust the signal voltage so that the detection crystal is in the working area of the calibration curve.
8.1.2.4 Connect the measured waveguide system between the test line and the matching load, move the measuring line probe, read the wave indication readings and ml of the maximum and minimum values of the standing wave electric field respectively, and then find out the corresponding calibration values and ml according to the calibration curve of the crystal detector. Calculate according to the following formula
Wherein, x
·relative maximum value of standing wave electric field;
F'ain
-relative minimum value of standing wave electric field
8.1.2.5 Change the signal source frequency and repeat 8.1.2.3 and 8.1.2.4 to measure the voltage standing wave coefficient of the measured waveguide system at other frequency points within the specified frequency band.
8.1.2.6 After the test, the results should be listed in a table. 8.1.3 Test frequency trap
The center frequency of the antenna is 0.For frequencies between 5 and 5 GHz, the frequency interval should not be greater than 0.025 GHz. For frequencies between 5 and 10 GHz, the frequency interval should not be greater than 0.05 GHz. For frequencies above 10 GHz, the frequency interval should not be greater than 0.1 GHz. 8.2 Swept frequency reflectometer ratiometer method
8.2:1 Test data diagram
The test block diagram is shown in Figure 2.
W. Sweep
Signal source
8.2.2 Test steps
X-ray recorder
GB.12201—90
Ratiometer
Oscilloscope
Directional combiner
(combined incident power)
Grid amplifier
Directional analyzer
(combined radiation power)
Figure 2 Block diagram of swept frequency reflectometer ratiometer method
8.2.2.1 Connect the test system as shown in Figure 2 and make it work normally. The movable short circuit breaker can be used to help the system under test to match the detection device. 8.2.2.2 Adjust the sweep frequency range of the sweep frequency signal source to the specified working range, set the sweep frequency selection to the "auto scan" position, and select a suitable sweep time. 8.2.2.3 Connect the movable short circuit breaker to the test system terminal, set the sweep frequency signal source to the point frequency position and adjust the frequency to the center frequency: Use the movable short circuit breaker to make the test terminal in the short circuit state and the open circuit state respectively. Set the tangent principle ratiometer to the 100% position, adjust the "full scale adjustment" knob of the ratiometer so that the swing average value of the ratiometer indicator pointer falls on the full scale value: If the ratiometer used is a logarithmic subtraction type, the decibel compensation knob of the ratiometer should be adjusted so that the open circuit and short circuit average values fall on the specified 0dB reference line. At the same time, it should be noted that the detector crystal should be in the square law working area at this time. 8.2.2.4 When using the tangent principle ratio timing, the reading indication scale on the ratio meter (which should include the maximum reflection coefficient value allowed by the waveguide system under test) should be drawn one by one on the scale plate of the oscillator or on the recorder paper. 8.2.2.5 Remove the movable short circuit, connect the terminal to the waveguide system under test with a matching load, and use the tangent principle ratio timing. The "quantity release switch" should be changed until the voltage reflection coefficient can be read on the ratio meter, and the scanning curve of the voltage reflection coefficient corresponding to the frequency change can be drawn on the XY recorder (or oscilloscope); if a logarithmic subtraction ratio meter is used, the return loss can be directly measured, and the scanning curve of the return loss corresponding to the frequency change can be drawn on the XY recorder (or 5
WG 12201---90
oscilloscope). 8.2.2.6 According to formula (3) and formula (5), the test results of 8.2.2.5 are plotted into voltage standing coefficient S and rate on coordinate curves to determine the wave coefficient of the waveguide system under test.
8.3 Sweep frequency reflectometer high frequency attenuation substitution method
8. 3. 1 Test block diagram
The test block diagram is shown in Figure 3.
Long afterglow speed photography
Or-receiver
Slope amplifier
Self (external)
Scan number part
8.3.2 Test steps
Detector
Directional post-closer?
(gate wave power)
Tester
Standard attenuator
Standard attenuator
(combined radiation rate)
Figure 3 Block diagram of high frequency attenuator for scanning radiation meter Removable short circuit
Tested technical system
Equipment
8. 3.2.1 Connect the test system according to Figure 3 and adjust the equipment to make it work properly. The standard attenuator in Figure 3 can also be placed between directional coupler ① and directional coupler ②.
8.3.2.2 Adjust the sweep frequency range of the sweep signal source to the specified working frequency band range + sweep frequency selection cover "automatic sweep gear", and select the appropriate sweep time.
8.3.2.3 The test system is terminated with a movable short circuit, the standard attenuator is placed in the 0 position, and the automatic amplitude stabilization circuit of the sweep signal source is switched to the external amplitude stabilization position. Then adjust the power control of the signal source and the gain knob of the automatic stabilization circuit to make the sweep signal source in the maximum amplitude stabilization power output state. At this time, the recorder or display is a basic horizontal straight line representing [|-1] with the maximum amplitude and the smallest fluctuation.
8.3.2.4 Remove the movable short circuit and replace it with the waveguide system under test with a terminal connected to a matching load. The standard attenuator is still at 0 dH. Position, carry out scanning measurement, the obtained curve represents the scanning curve of the relationship between the return loss and frequency of the measured waveguide system, center
W.GB12201-90
8.3.2.5 Remove the measured waveguide system, and then connect a movable short-circuit device. According to the change range of the return loss curve 2 of the measured waveguide system in 8.3.2.4, adjust the sliding attenuator so that the attenuation value gradually increases from zero to make a family of calibration curves with the same wave loss. In this way, the return loss value of any point on the measured curve can be determined.
8.3.2.6 According to formula (5), the above results are plotted into a voltage standing wave coefficient S and frequency coordinate curve to determine the wave coefficient of the measured waveguide system.
Additional explanation:
This standard is signed by Shanghai Marine Navigation Institute and Shanghai Radio Frequency Factory.2 Test steps
Detector
Directional coupler?
(gate wave power)
Detector
Standard attenuator
Standard attenuator
(exhaustion rate)
Figure 3 Block diagram of high frequency attenuator for scanning radiometer Removable short circuit
Tested system
Equipment
8. 3.2.1 Connect the test system according to Figure 3 and adjust the equipment to make it work properly. The standard attenuator in Figure 3 can also be placed between directional coupler ① and directional coupler ②.
8.3.2.2 Adjust the sweep frequency range of the sweep signal source to the specified working frequency band range + sweep frequency selection cover "automatic sweep gear", and select the appropriate sweep time.
8.3.2.3 The test system is terminated with a movable short circuit, the standard attenuator is placed in the 0 position, and the automatic amplitude stabilization circuit of the sweep signal source is switched to the external amplitude stabilization position. Then adjust the power control of the signal source and the gain knob of the automatic stabilization circuit to make the sweep signal source in the maximum amplitude stabilization power output state. At this time, the recorder or display is a basic horizontal straight line representing [|-1] with the maximum amplitude and the smallest fluctuation.
8.3.2.4 Remove the movable short circuit and replace it with the waveguide system under test with a terminal connected to a matching load. The standard attenuator is still at 0 dH. Position, carry out scanning measurement, the obtained curve represents the scanning curve of the relationship between the return loss and frequency of the measured waveguide system, center
W.GB12201-90
8.3.2.5 Remove the measured waveguide system, and then connect a movable short-circuit device. According to the change range of the return loss curve 2 of the measured waveguide system in 8.3.2.4, adjust the sliding attenuator so that the attenuation value gradually increases from zero to make a family of calibration curves with the same wave loss. In this way, the return loss value of any point on the measured curve can be determined.
8.3.2.6 According to formula (5), the above results are plotted into a voltage standing wave coefficient S and frequency coordinate curve to determine the wave coefficient of the measured waveguide system.
Additional explanation:
This standard is signed by Shanghai Marine Navigation Institute and Shanghai Radio Frequency Factory.2 Test steps
Detector
Directional coupler?
(gate wave power)
Detector
Standard attenuator
Standard attenuator
(exhaustion rate)
Figure 3 Block diagram of high frequency attenuator for scanning radiometer Removable short circuit
Tested system
Equipment
8. 3.2.1 Connect the test system according to Figure 3 and adjust the equipment to make it work properly. The standard attenuator in Figure 3 can also be placed between directional coupler ① and directional coupler ②.
8.3.2.2 Adjust the sweep frequency range of the sweep signal source to the specified working frequency band range + sweep frequency selection cover "automatic sweep gear", and select the appropriate sweep time.
8.3.2.3 The test system is terminated with a movable short circuit, the standard attenuator is placed in the 0 position, and the automatic amplitude stabilization circuit of the sweep signal source is switched to the external amplitude stabilization position. Then adjust the power control of the signal source and the gain knob of the automatic stabilization circuit to make the sweep signal source in the maximum amplitude stabilization power output state. At this time, the recorder or display is a basic horizontal straight line representing [|-1] with the maximum amplitude and the smallest fluctuation.
8.3.2.4 Remove the movable short circuit and replace it with the waveguide system under test with a terminal connected to a matching load. The standard attenuator is still at 0 dH. Position, carry out scanning measurement, the obtained curve represents the scanning curve of the relationship between the return loss and frequency of the measured waveguide system, center
W.GB12201-90
8.3.2.5 Remove the measured waveguide system, and then connect a movable short-circuit device. According to the change range of the return loss curve 2 of the measured waveguide system in 8.3.2.4, adjust the sliding attenuator so that the attenuation value gradually increases from zero to make a family of calibration curves with the same wave loss. In this way, the return loss value of any point on the measured curve can be determined.
8.3.2.6 According to formula (5), the above results are plotted into a voltage standing wave coefficient S and frequency coordinate curve to determine the wave coefficient of the measured waveguide system.
Additional explanation:
This standard is signed by Shanghai Marine Navigation Institute and Shanghai Radio Frequency Factory.
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