This standard specifies the test method for two-tone intermodulation distortion of linear amplifier tubes for transmitting tubes. This standard applies to the test of two-tone intermodulation distortion of linear amplifier tubes with space charge control and anode dissipation power of more than 25W for single-sideband multi-channel transmission independent carrier. GB/T 3789.24-1991 Test method for electrical performance of transmitting tubes Test method for two-tone intermodulation distortion of linear amplifier tubes GB/T3789.24-1991 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for electrical properties of transmitting tubes
Test methods for dual tone inter-modulation distortion of linear amplifier tubesSubject content and scope of application
This standard specifies the test methods for dual tone inter-modulation distortion of linear amplifier tubes. GB/T3789.2491
Replaces GB3789.24-83
This standard is applicable to the test of dual tone inter-modulation distortion of space charge controlled linear amplifier tubes (used for single sideband, multi-channel transmission, independent carrier, etc.) with anode dissipation power above 25W. 2 Reference Standards
GB/T 3789. 12
General Principles of Electrical Performance Test Methods for Transmitter Tubes
3 Terms
Dualtoneinter-modulatiandistortionoffinearamplifiertubesDualtoneinter-modulationdistortion refers to the ratio of the amplitude of the intermodulation side-frequency signal on the load within the passband to the amplitude of a single-tone signal in the dual-tone signal when the tube is under specified working conditions and using an equal-amplitude dual-tone signal as the test signal. 4 Square Pyramid Diagram
Equal-amplitude sound signal source
In the diagram: A—excitation signal monitoring point; B—anode load monitoring point of the tube under test.
5 Test equipment and test rules
Tuning
Frequency harmonic sub-instrument
(distortion test room)
5.1 Test equipment and test rules shall comply with the provisions of GB/T3789.1. 5.2 Requirements for test equipment
Approved by the State Administration of Technical Supervision on August 15, 1991Resistance negative
Change rate meter
Implementation on April 1, 1992
GB/T 3789.24-91
The intermodulation distortion index of the equal-amplitude two-tone signal source at the excitation level shall be more than 10dB better than the best intermodulation distortion value of the tube under test, and not worse than -60 dB,
The signal used shall be equal-amplitude two-tone, the frequency of the two-tone signal shall be between 1000~～2000Hz, and the test frequency shall be selected between 1.6～30MHz.
In order to stabilize the linear amplifier, a neutralization circuit is allowed, but it shall not affect the test accuracy. Envelope correction and high-frequency negative feedback are not allowed to improve intermodulation distortion.
Except for the anode power supply, each anode power supply voltage shall use a voltage stabilizing device with a stability of not less than 1%. The accuracy of the resistance load and power meter shall not be less than 5%. Spectrum analyzer:
The frequency range shall be 0.5~30MHz;
The sensitivity shall not be less than 100 dB/μV;
The amplitude measurement range shall be 0~～-60dB
The intermodulation distortion itself shall be better than -60dB.
(Other instruments are allowed, but they shall not affect the test accuracy). 5.3 The following values ​​shall be given in the electronic tube product standard: a
Maximum anode negative resistor:
Anode loop impedance, loop quality factor and its error range, test frequency.
6 Test methodwww.bzxz.net
Add the filament voltage and the DC voltage of each pole according to the specification, adjust the negative voltage of the first grid plate, make the anode current reach the specified value, and keep the excitation signal stable. 6.1
6.2 Adjust the tuning circuit and the excitation signal. At resonance, make the output power of the tube under test reach the specified value (the peak envelope power is equal to twice the average power).
6.3 Read the intermodulation distortion component of the tube under test. The third-order and fifth-order intermodulation distortion are calculated as follows: E(2f- f22 or Kus = 20 1og 4
E(2f2 — f1)
Kma = 20 log
B(3f 2) or Kms - 20 1og
E(3f2 — 2fl)
K = 20 1ag
K、KMi. High-order intermodulation distortion is similar to the above formula:
Third-order intermodulation distortion component, dB,
Fifth-order intermodulation distortion component, dB,
Dual-tone signal frequency;
E(251—J2), E(2f2一)—Amplitude of third-order intermodulation distortion component: R(3F1—2F); E(3f2—2f1)—-: Amplitude of fifth-order intermodulation distortion component; E(f1), E(f2)-Dual-tone signal amplitude.
. (1)
(2)
Additional explanation:
GB/T3789.24—91
This standard is proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard is drafted by the Electronic Standardization Institute of the Ministry of Machinery and Electronics Industry and the responsible person of Factory 779.
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