GB/T 3789.15-1991 Transmitter tube electrical performance test method Output power test method
Some standard content:
National Standard of the People's Republic of China
Test methods of the electrtcal properties of transmitting tubes
Test methods of output power
Measurements of the electrtcal properties of transmitting tubesMeasuring methods of output power Subject content and scope of application
This standard specifies the test methods of the output power of transmitting tubes. GB/T 3789.1591
Replaces GB 3789. 15
This standard applies to the test of the output power of space charge controlled oscillators and power amplifiers with anode dissipation power of more than 25W and a frequency lower than 1 000 MHz.
2 Referenced standards
GB/T 3789. 1
General principles for test methods of the electrtcal properties of transmitting tubes
3 Terms
Output poweroutput power
3.1 Output power refers to the continuous emission output power of the electron tube when the anode loop is resonant and the load is optimally matched under the specified working conditions.
3.2 Underheated output power refers to the continuous RF output power of the tube when the anode loop resonates and the load is optimally matched under the specified cathode underheated working state.
4 Test equipment and test ruleswwW.bzxz.Net
The test equipment and test rules shall comply with the provisions of GB/T3789.1. The fundamental resonance impedance of the loop shall be much higher than the harmonic impedance, and the loaded quality factor Q of its resonant loop shall not be less than 5. In the test equipment, a neutralization circuit is allowed but shall not affect the test accuracy. 5 Test method
5.1 Test method for tube output power of common cathode RF amplifier 5.1.1 Determine the output power by measuring the DC input power and the anode dissipation power. The calculation method is as follows: Pat = Ph- P.
Where P—!
Output power, kw;
Pa——DC input power of the tube anode, kW; P. Tube anode dissipation power, kW.
5.7.7.1 Measurement of input power Pa is as follows: PUI
Wherein: U
DC voltage between anode and cathode, kV;
Approved by the State Administration of Technical Supervision on August 15, 1991 (implemented on April 1, 1992)
DC basis of anode current, A.
5.1.2 Measurement of anode dissipated power P. 5.1.2.1 Measurement is carried out using the heat-mechanical equivalent method
For forced water-cooled electron tubes, calculation is made according to formula (3):
GB/T 3789.15-91
P, = 0.0695 Q(--t) - P,f -- Prl - Pg2 -Wu Zhong: e
water flow, L/mtn;
temperature of cooling water when it flows out,;
temperature of cooling water when it flows in,;
power radiated from the filament of the tube under test to the anode, kW: P,--power radiated from the first grid of the tube under test to the anode, WP2--power radiated from the second grid of the tube under test to the anode, kW. Evaporative cooling electron tube is calculated according to formula (4): b.
P. = C37. 4 Q + D. 069 5 Q(100 - t)3 - P — P-mt, - P-2(kw) In the formula, o-
Flow rate of water after condensation, L/min;
Temperature of water after condensation, ℃
Power radiated from the filament of the tube under test to the anode, kw:Power radiated from the first grid of the tube under test to the anode, kW;;Power radiated from the second grid of the tube under test to the anode, kW. 5.1.2.2 Measurement by substitution method
. (4)
Install a sensitive temperature indicator at an appropriate place near the tube under test. Tune the circuit to the specified oscillation state until the reading of the temperature indicator reaches a stable state. Then switch the tube under test to the static test state, change the first grid voltage so that the anode current is adjusted to the reading of the temperature indicator equal to the reading obtained in the oscillation state. At this time, the power P. dissipated by the anode in the oscillation state is approximately equal to the power dissipated in the static state.
Where: U.—anode voltage in static state, kV; I. anode current in static state, A.
P.au +I.(kW) +.
For tubes with natural cooling, the temperature indicator should be placed at the place where the anode dissipation of the tube shell is the largest; (5)
For tubes with forced air cooling, the air flow rate should remain unchanged. The temperature indicator should be placed at the same position of the air outlet; b.
For tubes with forced water cooling, the water flow rate should remain unchanged. The temperature indicator should be placed at the same position of the water outlet; c.
For tubes with evaporative cooling, the cooling conditions should remain unchanged. The temperature indicator should be placed at the same position of the cooling system d.
Note: () The temperature indicator used should take into account the influence of high-frequency radiation. ② The dielectric loss of glass should be taken into account during RF testing. @) The temperature difference between the inlet and outlet water (or inlet and outlet air) should be kept constant during testing. 5.1.3 Determine the output power by measuring the RF power on the equivalent load. P
Where: p
Electronic tube output power, kw
GB/T 3789. 1591
Pi—the rated power measured on the equivalent load, kW; —loop efficiency.
5.1.4 Measurement of the rated power P,
5.1.4.1Measure the power on the water-cooled equivalent load using the heat-work equivalent method and calculate it according to formula (7): P, - 0. 069 5 Q(tg - t,) (kW)Where: 0
Water flow rate, L/min,
Temperature of cooling water when it flows out, °C;,
Temperature of cooling water when it flows in, °C.
The power on the evaporative cooling equivalent load is calculated according to formula (8): Pr = 37.4Q + 0.0695Q(100-t)Where: Q—flow rate of water after condensation, L/min, - temperature of water after condensation, °C.
5.7.4.2Measure
by substitution method. Use the comparison method of photocell and incandescent bulb
(8))
Adjust the tube under test to the specified oscillation state, and use the incandescent bulb as the equivalent load of the tube under test. Then place the photocell at the appropriate position corresponding to the incandescent bulb of the equivalent load, and read the photocurrent in the photocell circuit. Then place the photocell at the appropriate position corresponding to the incandescent bulb of the comparison, so that the distance between the photocell and the incandescent bulb of the comparison is the same, and adjust the input power of the incandescent bulb of the comparison so that the photocurrent reading in the photocell circuit is the same as the reading measured in the previous step. At this time, the input power of the incandescent bulb is the power P. on the equivalent load measured. P, - U.1
Where: — is the voltage applied to the incandescent bulb, V1 is the current flowing through the incandescent bulb, Ab, measured by temperature difference comparison method
. According to the specification, add the filament voltage and the voltage of each pole, and then add the excitation voltage of the measured tube, adjust the anode circuit, so that the load can obtain the maximum power. At this time, there is a temperature difference A between the water inlet (air inlet) and the water outlet (air outlet) in the load resistor. Then disconnect the measured tube circuit, connect the comparison circuit, and adjust the voltage of the comparison circuit so that the temperature difference between the water inlet (air inlet) and the water outlet (air outlet) in the load resistor is also. Then the power on the equivalent load is calculated according to formula (10):
Where, U is the voltage applied by the comparison circuit, VR is the anode load resistance of the measured tube,. Note: The voltage applied in the substitution method is generally a DC voltage or a 60 Hz AC voltage. 5.1.4.3 Use a power meter that matches the output circuit to directly read the rated power PL. 5.1.4.4 Use the RF voltage method to measure
Where, U
The effective value of the RF voltage on the equivalent load, V, 172
(10)
The resistance of the equivalent load, 2.
5.1.5 Efficiency measurement
5.1.5.1 Determine the cold test circuit impedance Where: Z.
GB/T 3789. 15-91
The no-load equivalent parallel resonant impedance of the tube anode output circuit: -The loaded equivalent parallel resonant impedance of the tube anode output circuit. 5.1.5.2 Use the cold test loop quality factor to determine Qo
Where: ——The no-load quality factor of the electron tube anode output circuit, Q——The loaded quality factor of the electron tube anode output circuit. 5.1.5.3 Comprehensive method for measuring the fundamental power
(13)
Use method 5.1.1 to measure the output power P; use method 5.1.2. 1 to measure the RF power P; calculate the efficiency of the anode output circuit.
This method is used to verify the loop efficiency.
5.2 Test method for the output power of the electron tube of the common-pole emitter amplifier 5.2.1 Use method 5.1.1 to measure the output power of the electron tube. 5.2.2 When measuring the output power of the electron tube by method 5.1.2, the grid excitation power should be deducted. Pu =—(P.
Oln)(W)
1(PP,)
Where; the peak value of the emitter voltage between the first grid and the cathode, Vin—peak value of the fundamental component of the anode current A, P, the excitation power of the input circuit.
5.3 Test method for tube output power of self-excited oscillator 5.3.1 Measure the tube output power by the method of 5.1.1. (w)
5.3.2 When measuring the tube output power by the method of 5.1.2, the grid excitation power should be increased. Por = -(Pz + -
$,,)(w)
Where: t is the RF voltage value between the first grid and the cathode, V; i, is the peak value of the fundamental component of the first grid current, A. 5.4 Test method for tube output power when the cathode is underheated (14)
5.4.1 Under the rated filament voltage or filament current, adjust the tube to the working state specified in the detailed specification. At this time, keep the voltage of each pole unchanged, and reduce the filament voltage or filament current to the specified value. The voltage of each pole remains unchanged, readjust the coupling between the anode circuit and the load and adjust the anode circuit to make the output power reach the maximum value. At this time, the output power of the electron tube can be measured according to the above method. GB/T 3789,1591
5.4.2 Under the rated filament voltage or filament current, adjust the electron tube to the specified working state and measure the output power of the electron tube according to the above method. Then evenly reduce the filament voltage or filament current (other voltages remain unchanged) until the output power is reduced to the specified value. The filament voltage or filament current value read at this time should comply with the provisions of the detailed specifications. Additional remarks:
This standard was proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard was drafted by the Electronic Standardization Institute of the Ministry of Machinery and Electronics Industry and Factory 779.
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