This standard specifies the technical requirements for medium-speed data transmission transmission, reception and ground communication equipment in satellite communication earth stations, except for antenna subsystems and terminal equipment subsystems. This standard applies to medium-speed data transmission equipment with information rates of 2048kbit/s and 8448kbit/s in the 4/6GHz frequency band. This standard applies to the establishment and technical transformation of satellite communication earth stations and serves as a technical basis for manufacturing equipment. GB/T 11444.4-1996 Technical requirements for domestic satellite communication earth station transmission, reception and ground communication equipment Part 4: Medium-speed data transmission equipment GB/T11444.4-1996 Standard download decompression password: www.bzxz.net

GB/T 11444.4-1996
The various rules specified in this standard involve various equipment for medium-speed data transmission in domestic satellite communication earth stations. The formulation of this standard is conducive to the standardization of various imported equipment and domestic equipment currently operating on the Internet, and is conducive to the research, production and normal operation of such equipment and communication networks.
This standard is formulated with reference to the IESS-308 (ReV.6) standard of the International Telecommunications Satellite Organization (INTELSAT) and the national standard GB11443.5-94.
This standard is a continuation of the three standards GB11444.1--89~GB11444.3-89 in terms of content, and is compatible with these three standards. This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China; this standard is under the jurisdiction of the Telecommunications Science Research and Planning Institute of the Ministry of Posts and Telecommunications; the drafting unit of this standard is the First Research Institute of the Ministry of Posts and Telecommunications; the main drafters of this standard are Zhang Peikang, Zhu Yingqi, Wu Shoukang, Pan Xinkang, and Hong Xiaopei. 281
National Standard of the People's Republic of China
Technical requirements for transmitting, receiving and ground communication equipment used in domestic satellite communication earth stations
Medium-speed data transmission equipment
Part 4
Trarsmitter, receiver and ground communication equipment used in domestic satellite communication earth stations.-...Technical requirementsPart 4 :Intermediate data rate (IDR) transmission equipment1 Scope
GB/T 11444. 4.--1996
This standard specifies the technical requirements for transmitting, receiving and ground communication equipment for medium-speed data transmission in satellite communication earth stations, except for antenna subsystems and terminal equipment subsystems. This standard applies to medium-speed data transmission equipment with information rates of 2048 kbit/s and 8448 kbit/s in the 4/6 GHz frequency band. This standard applies to the establishment and technical transformation of satellite communication earth stations and serves as the technical basis for manufacturing equipment. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard by being referenced in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB11443.5-94 General technical requirements for domestic satellite communication earth stations Part V: Medium-speed data digital carrier channel GB7611-87 Pulse code modulation communication system network digital interface parameters CCITTV.35 Data transmission at a rate of 48kbit/s using a 60-108kHz base group circuit 3 Equipment composition
Medium-speed data transmission equipment is mainly composed of high-power amplifiers, medium-power amplifiers (optional), low-noise amplifiers, up-converters, down-converters, modulators and demodulators. The interface levels between each unit are recommended typical values. Each functional unit should provide a monitoring interface. And generally there should be a main and a standby, adapting to automatic or manual switching. 4 Equipment working conditions
a) Temperature: Indoor +5℃～+40℃;
Outdoor -35℃～+55℃;
b) Relative humidity: Indoor 5%～85%;
Outdoor 5%~95%;
c) Air pressure: 70kPa～106 kPa;bzxZ.net
d) Power supply: single-phase AC, voltage (220±22)V, frequency (50±1)Hz; or three-phase AC, voltage (380±38)V, frequency (50±1)Hz. Approved by the State Administration of Technical Supervision on December 18, 1996, and implemented on December 1, 1997
5 Equipment input and output connectors
5.1 RF
Coaxial N-50K
5.2 IF
Circular axis BNC-75K
5.3 High power amplifier output
FDM-70 waveguide flange
5.4 Low noise amplifier input
FDM-40 waveguide flange
6 Transmitting equipment
GB/T 11444.4 1996
Including high power amplifier and medium power amplifier (optional). High power amplifier can usually be a klystron amplifier, a traveling wave tube amplifier or a solid-state power amplifier.
6.1 High power amplifier
6.1.1 Frequency range
5925MHz~6425MHz (or extended to 5850MHz～6650MHz). 6.1.2 Output power
6.1.2.1 Klystron amplifier or traveling wave tube amplifier (saturated output power) 400W~1000W various levels.
6.1.2.2 Solid-state power amplifier (1dB gain compression point) 50W~500W various levels.
6.1.3 RF level adjustment
0～20dB continuously adjustable,
6.1.4 Gain
6.1.4.1 Klystron amplifier and traveling wave tube amplifier (6dB lower than the nominal value of saturated output power) are divided into three levels:
a) ≥75 dB;
b) 270 dB;
c) ≥65 dB.
6.1.4.2 Solid-state power amplifier
is divided into three levels:
a) ≥65 dB;
h) ≥60 dB;
c) ≥50 dB.
6.1.5 Gain slope
not worse than ±0.04dB/MHz (f±14.4MHz) Note: f. is the center frequency of the amplifier operating frequency band, the same below. 6.1.6 Gain stability
not inferior to ±0.25dB/d (at constant temperature, constant power supply voltage, constant excitation) 6.1.7 Instantaneous bandwidth
Klystron amplifier:
≥36MHz (in-band gain fluctuation 1dB);
Traveling wave tube amplifier: ≥500MHz (in-band gain fluctuation 3dB); 286
GB/T 11444.4—1996
Solid-state power amplifier: ≥500MHz (in-band gain fluctuation 2dB). 6.1.8 Amplitude/frequency characteristics
≤0.4 dB(pp)(fa±14.4 MHz); ≤1 dB(pp)(/.±18 MHz).
6.1.9 Input Standing Wave Ratio
Klystron amplifier and solid-state power amplifier: 1.25:1 (maximum); Traveling Wave Tube amplifier:
6.1.10 Output Standing Wave Ratio (cold state)
1.3:1 (maximum).
Klystron amplifier and solid-state power amplifier: 1.25:1 (maximum); Traveling Wave Tube amplifier:
6.1.11 Load Standing Wave Ratio
Klystron amplifier: 2.0:1 (maximum); Traveling Wave Tube amplifier: 1.5:1 (maximum). 6.1.12 Multi-carrier intermodulation ratio
1.3:1 (maximum).
Klystron amplifier: ≤-29dBc (when the total power of two equal carriers is 7dB lower than the saturated output power); traveling wave tube amplifier: ≤-24dBc (when the total power of two equal carriers is 7dB lower than the saturated output power); solid-state power amplifier: ≤-33dBc (when the total power of two equal carriers is 7dB lower than the output power of 1dB gain compression point). 6.1.13 AM/PM conversion coefficient
Klystron amplifier: ≤4/dB (when it is 6dB lower than the saturated output power); traveling wave tube amplifier: ≤3dB (when it is 6dB lower than the saturated output power); solid-state power amplifier: ≤1°/dB (when it is 6dB lower than the 1dB gain compression point). 6.1.14 Residual amplitude modulation
≤-40 dBc (F.<4 kHz);
≤-20(1+lgF.)dBc (4 kHz≤F≤500 kHz); ≤-80 dBc (F.>500 kHz).
Note: F is the center frequency of the measured 4kHz spectrum, kHz. 6.1.15 Residual frequency modulation
Not worse than -60dB (relative to 4MHz peak-to-peak frequency deviation in any 5MHz bandwidth) 6.1.16 Group delay/frequency characteristics
Klystron amplifier and traveling wave tube amplifier (in each 36MHz bandwidth): Linearity: better than ±0.05ns/MHz;
Parabola: better than ±0.01ns/MHz;
Ripple: ≤l ns(pp).
Solid-state power amplifier:
Linearity: better than ±0.04ns/MHz;
Parabola: better than ±0.005ns/MHz2; Ripple: ≤1ns(pp).
6.1.17Noise and spurious
≤ -- 65 dBW /4 kHz (4.2 GHz-~12.0 GHz); ≤ -- 130 dBW /4 kHz (3.7 GHz~4.2 GHz); ≤--110 dBW/MHz (12 GHz～40 GHz). 6.1.18RF leakage (cabinet radiation)
≤1 mW/cm (5 cm from the cabinet).
6.2 Medium power amplifier (optional)
6.2.1 Frequency range
GB/T 11444. 4--1996
5 925MHz～6 425MHz (or extended to 5850MHz～6 650MHz). 6.2.2 Output power (1dB gain compression point) 100mW~1W various levels.
6.2.3 Gain
Divided into three levels:
a) ≥20 dR;
b) ≥30 dB;
c) ≥40 dB.
6.2.4 Gain flatness
Not inferior to +1dB (500MHz).
6.2.5 Input standing wave ratio
1.5:1 (maximum).
6.2.6 Output standing wave ratio
1.5:1 (maximum).
6.2.7 Noise figure
10 dB.
6.2.8 Third order intermodulation intercept point
≥40dBm (for 1W output), and so on. 7 Receiving equipment
Usually uses low noise field effect amplifier
7.1 Frequency range
3700MHz~~4200MHz (or extended to 3400MHz4200MHz). 7.2 Noise temperature
30K～55K various levels (at 25C).
7.3 Amplitude/frequency characteristics
7.3.1 Within 500MHz bandwidth:
S1 dB(pp).
7.3.2 In each 36MHz bandwidth:
≤0. 8 dB(pp).
7.4 Gain
Divided into two levels:
a) ≥60 dB;
b) ≥50 dB.
7.5 Gain slope
Not worse than ±0.03dB/MHz.
7.6 Gain stability
7.6.1 Gain stability is divided into:
Short term: not worse than ±0.1dB/h;
Medium term: not worse than ±0.2dB/d;
Long term: not worse than ±0.5dB/week.
GB/T 11444.4—1996
7.6.2 Within the temperature range of 35℃～+55C, the gain variation is allowed to be ±2.7dB. 7.7 Maximum output (1dB gain compression point) +10 dBm.
7.8 Input standing wave ratio
1.25:1 maximum).
7.9 Output standing wave ratio
1.25:1 (maximum).
7.10 Group delay/frequency characteristics (in each 36MHz bandwidth) Linearity: better than ±0.05ns/MHz;
Parabola: better than ±0.01ns/MHz2.
Ripple: ≤0.5 ns(pp).
7.11 Multi-carrier intermodulation ratio
≤-51dBc (when the total output of two equal carriers is 7dBm). 7.12 AM/PM conversion coefficient
≤0.5°/dB (at 7 dBm output).
7.13 In-band overload performance
When inputting 10 dBm, the performance does not deteriorate permanently. 7.14 Out-of-band characteristics
When inputting a signal within the transmission band of 10 dBm, it operates normally. 7.15 Spurious
Below thermal noise power (100 kHz bandwidth test). 8 Ground communication equipment
8.1 Upconverter
8.1.1 Frequency conversion method
Two frequency conversions.
8.1.2 Input frequency
70 MHz ± 18 MHz (or 140 MHz ± 36 MHz).
8.1.3 Input impedance
750.
8.1.4 Input return loss
≥26 dB.
8.1.5 Output frequency
5925MHz~～6425MHz (or extended to 5850MHz~～6650MHz). 8.1.6 Output impedance
500.
8.1.7 Output return loss
≥20 dB.
8.1.8 Rated output level
≥--10 dBm.
8.1.9 Gain
≥10 dB.
8.1.10 Output level stability
Not worse than ±0.25dB/d.
8.1.11 Frequency stability
Not worse than ±5×10-8/month.
8.1.12 Amplitude/frequency characteristics
≤0.5 dB(pp) (f,±18 MHz)
≤1 dB(pp) (fo±36 MHz)
GB/T11444.4-—1996
Note: It is the center frequency of the inverter working frequency band, the same below. 8.1.13 Group delay/frequency characteristics (in each 36MHz bandwidth) Linearity: better than ±0.03ns/MHz;
Parabola: better than ±0.01ns/MHz*
Ripple: ≤1 ns(pp).
8.1.14 Multi-carrier intermodulation ratio
≤--40 dBc (when the total output of two equal carriers is 7dB lower than the rated output level). 8.1.15 Local oscillator leakage
≤-70 dBm.
8.1.16 Spurious
≤--80 dBm/4 kHz.
8.1.17 Phase noise
8.1.18 Frequency control
100 Hz
10 kHz
100kHz
≤--63 dBc/Hz;
≤-73 dBc/Hz;
≤-83 dBc/Hz;
≤-93 dBc/Hz.
Adjusted by frequency synthesizer, step 125kHz (or 250kHz). 8.2 Downconverter
8.2.1 Frequency conversion method
Double frequency conversion.
8.2.2 Input frequency
3 700 MHz--4 200 MHz (or extended to 3 400 MHz-~4 200 MHz)8.2.3 Input impedance
502.
8.2.4 Input return loss
≥20 dB.
8.2.5 Input level range
-70 dBm~-- 40 dBm.
8.2.6 Output frequency
70 MHz±18 MHz (or 140 MHz±36 MHz).8.2.7 Output impedance
752.
8.2.8 Output return loss
≥26 dB.
8.2.9 Gain
≥30 dB.
8.2.10 Gain stability
Not worse than ±0.25dB/d.
8.2.11 Frequency stability
Not worse than ±5×10-8/month.
8.2.12 Noise figure
≤15 dB.
8.2.13 Amplitude/frequency characteristics
≤0.5 dB(pp) (±18 MHz)
≤1 dB(pp) (fo±38 MHz)
GB/T 11444.4-1996
8.2.14 Group delay/frequency characteristics (in each 36MHz bandwidth) Linearity: better than ±0.03ns/MHz
Parabola: better than ±0.01ns/MHzz
Ripple: ≤l ns(pp)
8.2.15 Multi-carrier intermodulation ratio
≤—45dBc (when the total output of two equal carriers is—15dBm). 8.2.16
Local oscillator leakage
≤-75 dBm.
8.2.17 Spurious
≤- 75 dBm/4 kHz.
8.2.18 Image rejection ratio
≥60 dBc.
Phase noise
8.2.20 Frequency control
100 Hz
100kHz
≤—63 dBc/Hz;
≤-- 73 dBc/Hz;
≤-83 dBc/Hz;
≤-93 dBc/Hz.
Adjusted by frequency synthesizer, step 125kHz (or 250kHz). 8.3 Modulator
The block diagram of modulator/demodulator is shown in Figure 1.
8.3.1 Modulation mode
Quadrature phase shift keying modulation, the relationship between the transmitted bit code and the modulator output carrier phase is shown in Table 1. Table 1
Transmitted bit code
Synthesized phase
+180°
+270°(90°)
The output phase accuracy of the modulator is better than ±2°, and the amplitude accuracy is better than ±0.2dB. The modulator is absolute phase modulation. The 180° carrier phase ambiguity is eliminated by differential coding in the FEC encoder. 8.3.2 Output power
-*- 30 dBm ~~ -10 dBm step 0. 5 dB. 8.3.3 Stability
Not worse than 0.25 dB/d.
8.3.4 Output frequency
8.3.4.1 Range
GB/T11444.4---1996
70 MHz±18 MHz (or 140 MHz±36 MHz). 8.3.4.2 Step
≤22. 5 kHz (or 2. 5 kHz).
8.3.4.3 Stability
Not worse than 3×10-7/month.
8.3.5 Spurious output
≤-50 dBc;
40 dBc.
8.3.6 Output impedance
8.3.7 Output return loss
≥20 dB.
8.3.8 Transmit filter characteristics
8.3.8.1 Filter amplitude response characteristics
See Figure 2.
8.3.8.2 Filter group delay response characteristics
See Figure 3.
8.3.8.3 Output power spectrum density tolerance
See Figure 4.
8.3.9 Information rate
The information rate is divided into the following two types: 2048 kbit/s and 8448 kbit/s. 8.3.10 Phase noise
8.3.11 Scrambler
According to CCITT V.35.
8.3.12 Encoder
See Figure 5.
8.3.12.1 Coding method
100kHz
Convolutional coding (see Figure 5).
8.3.12.2 Coding rate
3/4.
8.3.12.3 Constraint length
8.4 Demodulator
8.4.1 Demodulation method
Coherent four-phase demodulation.
8.4.2 Input level
8.4.2.1 Range
-55 dBm~-35 dBm.
8.4.2.2 Maximum synthetic input level
--10 dBm.
≤-63 dBc/Hz;
≤93 dBc/Hz.
8.4.3 Input frequency
8.4.3.1 Range
GB/T 11444.4-1996
70MHz±18MHz(or 140MHz±36 MHz). 8.4.3.2 Step
≤22. 5 kHz(or 2.5 kHz).
8.4.4 Input impedance
752.
8.4.5 Input return loss
≥20dB.
8.4.6 Capture range
8.4.6.1 Carrier capture range
±25kHz(relative to nominal input frequency). 8.4.6.2 Clock capture range
±10-1.
8.4.7 Information rate
The information rate is divided into the following two types: 2048 kbit/s and 8448 kbit/s. 8.4.8 Receive filter characteristics
8.4.8.1 Filter amplitude response characteristics
See Figure 6.
8.4.8.2 Filter group delay response characteristics
See Figure 3.
8.4.9 Decoder
8.4.9.1 Decoding method
Soft decision Viterbi decoding.
8.4.9.2 Decoding rate
3/4.
8.4.9.3 Constraint length
K=7.
8.4.10 Bit error rate performance (modem intermediate frequency loop measurement) P
Descrambler
E/N.
According to CCITT V.35.
8.5 Frame unit
8.5.1 Header generator
8.5.1.1 Header frame generator
See Figure 7 (information rate is 2048kbit/s) and Figure 8 (information rate is 8448kbit/s). The header (OH) is 12 bits long and is divided into three parts: a) The first 4 bits are used for alarm, signaling and digital ESC data. Each group of alarm signals and signaling is transmitted within 8 frames, so every 8 frames constitute a multiframe. The multiframe period is 1ms.
b) Bits 5 to 8 are for the first ESC voice channel, with a rate of 32kbit/s. 293
GB/T 11444.4--1996
c) The 9th to 12th bits are for the second ESC voice channel, with a rate of 32kbit/s. 8.5.1.2 Positioning of frames and frames
The positioning of frames and frames is marked by the first "positioning bit" of each frame in the frame. The positioning bits include the first bit of each frame and the second, third, and fourth bits of the first, third, fifth, and seventh frames in the frame. The formats of these bits are shown in Figures 7 and 8. When the frame is out of sync, if there are no errors in the continuous search of 4 frame synchronization codes, it indicates frame synchronization: when the frame is synchronized, if there are errors in the continuous search of 1 frame synchronization code, it indicates that the frame is out of sync and the synchronization code needs to be recaptured. 8.5.2 Doppler and quasi-synchronous buffer
The buffer capacity is related to the satellite perturbation and timing accuracy. Its minimum capacity is in accordance with the requirements of GB11443.5. 8.5.3 Engineering Service Circuit (ESC)
a) The clock in the ESC equipment should be extracted from the received and transmitted data streams; b) FSC can provide 2-way ADPCM (32kbit/s) official telephone; c) ESC can provide 1-way low-speed (8kbit/s) ESC data (this information should be placed in "1\" when not in use); d) Voice interface
Transmit level -20 dBr: Receive level
-2 dBr.
8.5.4 Terminal (or DCME) interface
See the relevant chapters of GB7611---87.
8.5.5 Monitoring function
The unit has the function of sampling the working status of the modulator, demodulator, up-converter, down-converter, transmitter and receiver, and indicates and sounds alarms on the monitoring panel. At the same time, the alarm indication signal (AIS) is processed based on the sampling, and the processing result is also displayed on the panel, and the processing result is fed to the opposite end or the local end. The alarm diagram is shown in Figure 9.
8.5.6AIS signal status and fault conditions are shown in Table 2.8.5.7Local backup clock
1×10-5/month.
Detected fault
From ground network via interface
A to modulation channel
From satellite line via
Interface E to demodulation channel
Fault handling measures
Via interface H to ground network
Via interface IID to satellite line
Detected fault
1) This function can only be realized in actual circumstances. 2) Part AH1 is not mandatory
AD2:
GB/T 11444.4--- 1996
Table 2 (end)
Failure of modulator, up-converter and transmitting equipmentFailure of demodulator, down-converter and receiving equipmentLoss of signal on the ground side (data or clock)Loss of signal on the satellite side
Out of step
Error code greater than 1×10*3
Remote station alarm
Emergency maintenance alarm
Maintenance alarm
Alarm to the ground direction
Alarm to the opposite station
Alarm to the opposite station
Decoder
Decoder
Figure 1 Block diagram of modulator/demodulator
221241112
0.1K 0.2R 0.3R 0.4R 0.5R 0.6R 0.7R Normalized frequency of the 0.8R offset center, Hz
Fault handling measures
Modulator
Demodulator
Coordinates of the point
Amplitude, dB
Note: The filter response characteristic is not a mandatory requirement, but it is used to specify the required emission spectrum. Figure 2 Modulator filter amplitude response characteristic
Normalized frequency, Hz
R=Transmission rate (bit/s)
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