This standard specifies the performance requirements of medium-speed data (IDR) digital carrier channels operating in Class I, Class II and Class III standard earth stations. This standard specifies the information rate, header rate, transmission rate, coding method, modulation method, engineering service circuit and maintenance alarm format of medium-speed data digital carrier channels. This standard applies to domestic health communication earth stations for fixed services (4/6GHz frequency band). It is not only applicable to domestic satellite communication systems composed of domestic communications and health, but also to domestic satellite communication systems composed of leased international communication satellite transponders. This standard is applicable to public communication networks and can also be used in private communication networks. This standard applies to the establishment and technical transformation of satellite communication earth stations. This standard applies to telephone services and non-telephone services. GB/T 11443.5-1994 General technical requirements for domestic satellite communication earth stations Part V: Medium-speed data digital carrier channels GB/T11443.5-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
General Technical Requirements for Domestic Satellite Communication Earth Stations Part 5: Intermediate Data Rate (IDR) Digital Carrier Channels1 Subject Content and Scope of Application
CB/T 11443.5--94
This standard specifies the performance requirements for intermediate data rate (IDR) digital carrier channels operating in Class I, Class II and Class III standard earth stations. This standard specifies the information rate, header rate, transmission rate, coding method, modulation method, engineering service circuit and maintenance alarm format of intermediate data digital carrier channels. This standard applies to domestic satellite communication earth stations in fixed service (4/6GHz frequency band). It applies not only to domestic satellite communication systems composed of domestic communication satellites, but also to domestic satellite communication systems composed of leased international communication satellite transponders. The former is referred to as "domestic satellite system" and the latter is referred to as "rented satellite system". This standard applies to public communication networks and can also be used in dedicated communication networks. This standard applies to the establishment and technical transformation of satellite communication earth stations. This standard applies to telephone services and non-telephone services. 2 Reference standards
GB11443.1 General technical requirements for domestic satellite communication earth stations Part - General requirements GB7611 Pulse code modulation communication system network digital interface parameters 3 Terms and codes
3.1 Terms
3.1.1 Transmission rate transmission rate (R) The bit rate after the information header bits are FEC-coded. 3.1.2 Viterbi decoding soft-decision maximun likelihood decoding (VITERBI)) Soft-decision maximum likelihood decoding.
3.2 Code
3.2.1IDR Medium-speed data
3.2.2ADPCM Adaptive Differential Pulse Code Modulation3.2.3ESC Engineering Service Circuit
3.2.4CFDM/FM Compressed Spread Spectrum Division Multiplexing/Frequency Modulation3.2.5DCME Digital Circuit Multiplication Equipment
3.2.6LRE/DSI Low Bit Rate Encoding and Digital Voice Interleaving Approved by the State Administration of Technical Supervision on December 28, 1994 and implemented on August 1, 1995
4 Modulation method
GB/T 11443.5-94
The information rate of the medium-speed data digital carrier is from 61 to 8448 kbit/s, using coherent four-phase phase-shift keying modulation. All medium-speed data carriers must use 3/4 rate FEC encoding and decoding (3/4 rate convolutional coding/Viterbi decoding). 5 Bit Error Rate (BER) Performance
Under clear sky conditions, the bit error rate should be less than or equal to 1×10-7 for more than or equal to 95.90% of the time throughout the year; under severe weather conditions, the bit error rate should be less than or equal to 1×106 for more than or equal to 99.36% of the time throughout the year; under severe weather conditions, the bit error rate should be less than or equal to 1×10-3 for more than or equal to 99.96% of the time throughout the year. 6 IDR carrier channel frequency configuration
The earth station intermediate frequency equipment must be equipped with a frequency synthesizer to adapt to changes in the service matrix, and the transmit and receive carrier frequencies should be configured at a frequency interval of 22.5kHz.
7 Information Rate Classification
The information rate is divided into the following five types: 64, 192, 384, 2048, 8448kbit/s. 8 Equivalent isotropic radiated power (EIRP)
To obtain the lowest possible transmit EIRP, the leased transponders in the "rented satellite system" are in high gain mode. Table 1 specifies the maximum FIRP required for IDR carriers. The actual operating EIRP will be equal to or less than the maximum value listed in Table 1. 8.1 EIRP correction factor
The maximum EIRP values ​​listed in Table 1 are the values ​​applied to the earth station at an elevation angle of 10° and at the edge of the beam. For the case where the earth station is located at a non-satellite antenna beam edge when the elevation angle is not 10°, the correction factor K1 should be subtracted: K, 0.02(αu —10) + β + 0.02(αa - 10) + βa) where: α-the elevation angle of the transmitting earth station, in degrees; ad
-the most unfavorable receiving earth station elevation angle, in degrees; βu---the difference between the gain at the edge of the satellite receiving antenna beam and the gain in the direction of the transmitting earth station, in decibels: Ba
-partial reception factor, for IDR carriers with a rate below 8448kbit/s, = 0.4. Table 1 requires maximum EIRPdBW for international V, VA, V satellites, hemispherical beam, high gain mode
Information rate
kbit/s
Note: (DA is international satellite V (F1~F4). GB/T 11443.5---94
②B is all channels of international satellite (F5~F9), VA (F10~F12) 9th channel, VA (IBS) (F13~F15) 9th channel ③C is international satellite VAF10~F12) except 9th channel, VA (IBS) (F13~F15) except 9th channel and V (F1F5) 9th channel. ④D is international И (F1~F5) except 9th channel. 8.2EIRP Adjustment
Under clear sky conditions, the required EIRP for each carrier is a function of the satellite sensitivity and the satellite power required in the corresponding satellite-to-earth station area in the transmission route. The EIRP transmitted by the earth station should be able to adapt to the requirements of level changes. Therefore, the EIRP transmitted by the earth station should have the ability to adjust 15dB downward from the specified EIRP maximum value. 8.3EIRP Stability
The EIRP of any IDR carrier transmitted by the earth station should be kept stable within ±0.5dB/d except in severe weather conditions. This indicator includes unstable factors such as high power amplifier output power instability (including the influence of the pre-excitation circuit), antenna transmission gain instability, antenna pointing error and tracking error. Under severe weather conditions, the power flux density at 6GHz on the satellite can be allowed to be 2 dB lower than the normal value, which will allow the corresponding receiving earth station channel performance to be reduced. 9 Radiation Limits
9.1 Spurious Radiation Components
The spurious radiation EIRP (including parasitic single-frequency signals but excluding intermodulation signals) transmitted by the earth station shall not exceed 4dBW in any 4kHz bandwidth in the 5925~6425MHz and 14000-14500MHz bands outside the allocated frequency bands. The spurious products falling within any 4kHz bandwidth allocated to each IDR carrier bandwidth shall be less than 40dB of the unmodulated carrier for rates below 2.048Mbit/s (including its own rate); and less than 50dB of the unmodulated carrier for rates above 2.048Mbit/s. 9.2 Transmitting multi-carrier intermodulation products
In the satellite system, in the frequency range of 5925~6425MHz, when the antenna elevation angle is 10, the intermodulation product EIRP generated by the earth station transmitting multiple carriers should not exceed 21dBW in any 4kHz bandwidth. When the elevation angle is other values, the correction factor 0.02(α-10)dB should be subtracted. Where: α is the earth station antenna elevation angle, in degrees. 9.3 RF out-of-band radiation (carrier spectrum sidelobe) Outside the frequency band used, each transmitted digital carrier sidelobe should be more than 26dB lower than the peak of the spectrum main lobe in any 4kHz bandwidth. The above restrictions only apply to spectral sidelobes caused by the nonlinear spectral diffusion of the earth station. In the frequency range of 0.35RHz to 0.5RHz from the nominal center frequency, the EIRP density shall be at least 16dB less than the peak EIRP density in any 4kHz bandwidth.10 Modulation Conversion
High power amplifiers with IDR carrier, FDM/FM carrier, CFDM/FM carrier multi-carrier operation shall cause modulation conversion due to the AM/PM (amplitude-phase conversion) characteristics. In any channel of the baseband of FDM/FM or CFDM/FM carrier, the single-tone modulation conversion T interference shall not be greater than -73 dBmOp.
11 Frequency Tolerance and Spectrum Inversion
11.1 RF Carrier Tolerance
The RF carrier tolerance (maximum error of initial frequency adjustment plus long-term drift) transmitted by all earth stations shall be ±0.025RHz, with a maximum of ±3.5kHz, and long-term means at least one month. The frequency stability of the earth station receiving link should be compatible with the frequency acquisition and tracking range of the demodulator, but it is recommended that its value is not worse than ±3.5 kHz.
11.2 Spectral inversion
The transmitted RF carrier spectrum should not be inverted relative to the modulator output spectrum. 12 Amplitude and group delay equalization
12.1 Earth station
GB/T11443.5--94
The amplitude and group delay response of the earth station refers to the response of the transmit link and the receive link. The transmit link is from the output of the modulator to the transmit antenna feed port; the receive link is from the receive antenna feed port to the demodulator input. The amplitude and group delay response should be equalized separately, and the transmit link should be kept within the tolerances shown in Figures 1 and 2. It is recommended that the receive link equalization should also be kept within the tolerances shown in Figures 1 and 2. 12.2 Satellite channel
The group delay response of the satellite input and output multiplexers depends on the position of the carrier in the transponder, which is compensated by the equalization of the earth station transmit link. The requirements for the international V satellite group delay equalization are shown in Table 2. Table 2
4.5≤BW<13.5
ns/MHz
0～±5
Parabolic equalization
ns/(MH2)2
Note: 1) If the satellite group delay parabola component is positive, then, in order to obtain equalization, the earth station should insert a negative parabola component. 13 Phase noise
13.1 Earth station (transmitting)
Single sideband phase noise includes continuous components and spurious components. The single sideband phase noise on the transmit carrier should meet the following limits: The single sideband power spectrum density of the continuous component should not exceed that shown in Figure 3. The spurious component at the power supply fundamental frequency should not exceed -30dB relative to the transmit a.
carrier, and the sum of all other spurious components (power addition) should not exceed -36dB relative to the transmit carrier (the total phase noise of the two sidebands can be 3dB higher). b. In the bandwidth range of 10Hz to 0.3RHz from the center frequency, the phase noise of the single sideband superimposed by continuous and spurious should not exceed 2.0°rms, and the total phase noise of the two sidebands should not exceed 2.8°rms. When the information rate is higher than 2.048Mbit/s, the requirements for phase noise are not mandatory.
13.2 Earth station (receiving)
It is recommended to be the same as 13.1.
14 Transmission performance
The transmission parameters of the IDR carrier are shown in Table 3. Table 3
Information rate
Preamble rate
Composite data rate
Information rate + preamble rate
kbit/s
The transmission characteristics of the IDR carrier operation are shown in Table 4. 22.1
Transmission rate
Occupied bandwidth
Allocated bandwidth
1. Information rate
GB/T 11443.5 ---94
64-~8448 kbit/s
2. Information rate greater than 2.048Mbit/s Carrier header data rate 3. Forward error correction coding
4. Energy dispersal (scrambling)
6. Ambiguity resolution
7. Clock recovery
8. Minimum carrier bandwidth (allocated)
9. Noise bandwidth (or occupied bandwidth)
10. Eb/N, corresponding to bit error rate (3/4 Forward error correction code rate) a. Modulation and demodulation self-loop
b. Through satellite channel
11. Working point C/T
12. Working point C/N in noise bandwidth
13. Working point bit error rate
14. Threshold C/T
15. Threshold C/N in noise bandwidth
16. Threshold bit error rate
15 Channel unit characteristics
96 kbit/s
3/4 convolutional coding/Viterbi decoding as per Figure 4
as per Figure 5 and Figure 6
Quadrature coherent phase shift keying
Combination of differential coding (180°) and forward error correction (90°)The timing clock must be recovered from the data stream
0.7RHz or [0.933 (information + header) rateIHz0.6RHz or [0.8 (information + header) rate] Hz10-3
一219.9+10lg[（information + header）rate],dBW/K9.7dB
1×10°?
222.9+10Ig[（information + header）rate]dBW/K6.7dB
1×10-3
The channel unit includes a modem, a forward error correction codec, a scrambler and a header frame generation unit. When the information rate is greater than 2.048Mbit/s, a header with a rate of 96kbit/s is inserted for engineering service circuits (ESC) and maintenance alarms.
15.1 Modulator
The modulator receives two parallel data streams from the FEC encoder, defined as the P channel and the Q channel. 15.1.1 Output characteristics
The relationship between the transmitted bit code and the modulator output carrier phase is shown in Table 5. Table 5
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. 225
15.1.2 Output spectrum
GB/T 11443.5—94
Within the frequency range of ±0.35RHz deviating from the nominal center frequency, it is the same as the output spectrum of a filter connected after an ideal modulator when the following conditions are met.
a. The input to the QPSK modulator is a non-return-to-zero random sequence code of Rbit/s: b. The filter has the bat characteristic given in Figure 7; the filter has the group delay characteristic given in Figure 8, or the phase response c.
should deviate from the linear phase shift by no more than ±1° within the range of ±0.25KHz from the nominal center frequency. The tolerance of the power spectral density output by the modulator is shown in Figure 9. For the frequency band outside the nominal center frequency ±0.75RHz, the intermediate frequency spectrum density output in any 4kHz bandwidth should be less than the peak spectrum density by 40dB
15.2 Demodulator
A coherent demodulator is used. The recovered clock and signal are fed to the FEC decoder, and the output of the demodulator is compatible with the soft decision decoder.
15.2.1 Working characteristicsbzxz.net
In the case of adjacent channel interference, and when both the desired carrier and the interfering carrier are allowed to deviate from the nominal carrier frequency ±25kHz, the channel unit should be able to meet the bit error rate performance requirements. Factors causing frequency deviation include the earth station's transmit link satellite local oscillator, Doppler shift and the earth station's receive link.
When the allowed adjacent channel interference has the same transmission rate as the desired carrier, the interference level can be 7 dB higher than the desired carrier at the frequency of the nominal center frequency of the desired carrier ± 0.7 Hz. 15.2.2 Demodulator filter characteristics
To obtain bit error rate performance, the demodulator filter should be designed with the amplitude characteristics given in Figure 10 and the group delay characteristics given in Figure 8. 15.3 Forward error correction
All rate carriers use 3/4 code rate convolution coding with Viterbi decoding. 15.3.1 Encoder
The 3/4 code rate convolution encoder shown in the schematic diagram of Figure 4 is used. This is a "constricted" convolutional code, which is formed by periodically deleting specific bits in the 1/2 code stream from the output bit stream of the 1/2 code rate encoder. The 1/2 code rate generating polynomial is octal 133 and 171. Therefore, before encoding, the data stream entering the 1/2 code rate convolutional encoder has completed differential encoding. 15.3.2 Decoder
The method of inserting the deleted bit code into the received data stream at the appropriate position first restores the 1/2 code rate. The insertion position is the bit code that was deleted after the code rate was 1/2 at the transmitting end, and then the decoding is completed. The restored 1/2 code rate coded data is decoded by the Viterbi decoder. The characteristics of the
decoder are as follows:
a. The coding gain should be adapted to the required E/N. For the 3-bit (8-level) quantized form, the decoder input requires the demodulator to have a corresponding gate.
b. There is internal 90° carrier phase ambiguity resolution and bit synchronization. c. Binary differential decoding with serial output data stream. d. It is recommended to have a bit error rate indication for monitoring carrier performance. 15.4 Energy Dispersion (Scrambling)
A digital scrambler is used at the transmitting earth station. Figure 5 shows the equivalent logic diagram of the scrambler, and Figure 6 shows the pulse response diagram of the descrambler. The FEC encoder should be located after the scrambler, and the decoder should be located before the descrambler at the receiving earth station. 15.5 Bit Error Rate Performance Characteristics
In channels using scramblers and forward error correction coding, the IF self-loop channel should achieve the following bit error rate performance characteristics. 226
BER (better than)
GB/T 11443.5-94
E/N. Depends on the modulated carrier power and the composite data rate entering the FEC encoder. 15.6 ESC and Alarm Header Frames
The header lazy format applies to IDR carriers with information rates of 2.048 and 8.448 Mbit/s. The information data stream passes through the header unit transparently without embedding the information content within the frame into the information data stream. 15.6.1 Header Frame Structure
The transmitted data stream consists of the IDR recovery structure and the 96 kbit/s header is added synchronously. The transmitted composite data stream derives the clock from the input information data stream. When the clock in the input information data stream fails, a backup clock source with a long-term stability of at least 10-\/month is used to generate the required timing. If the input transmission data pulse is interrupted, or the clock source is interrupted, or both are interrupted, the header unit should be designed to continue to work. The receiving end header unit recovers the clock from the received data stream. The structure is derived by adding 12 bits to every 125us (2.048Mbit/s information). The header bits are allocated as follows: a. 4 bits are used for backward alarm and ESC data for frame and frame positioning, a total of 32kbit/s: the data at this rate has the following functions:
20kbit/s for frame and frame positioning;
4kbit/s can be used for backward alarm of 4 addresses (1kbit for each address); 8kbit/s for ESC data.
b. 8 bits are used for two 32kbit/s ESC voice channels, a total of 64kbit/s. The header structure is shown in Figure 11 (information rate is 2.048Mbit/s) and Figure 12 (information rate is 8.448Mbit/s). The header unit at the transmitting end adds the ESC and alarm information to the transmitted information stream to form a composite data stream and feeds it to the scrambler. The header information is not embedded in the transmitted information stream. The opposite processing is completed at the receiving end. The capacity of the header unit is two digitized voice channels or voice in-band data for ESC, and an 8kbit/s data signal (if not used, set to \1\). The ESC equipment can separate the receiving and transmitting clocks at 32kHz, 8kHz, and 1kHz frequencies. The 1kHz clock is synchronized with the frame rate, and other outputs are synchronized with this 1kHz clock. The header unit has the function of detecting the alarm status and generating timing for maintenance, and can also generate four separate backward alarm signals.
Frame and reset positioning is realized by array signals, with eight-bit codes inserted into the first bit of each frame, and twelve-bit codes inserted into the second, third and fourth bits of odd-numbered frames, as shown in Figures 11 and 12. When one or more errors are received in four consecutive positioning signals, the frame and reset positioning is considered lost. When the correct positioning signal is detected for the first time, the frame and reset positioning is considered to be restored. When positioning is lost, the header detection circuit will be placed in a continuous positioning signal search state. When the positioning signal is received correctly, the header detection circuit timing is restored. 16 Buffering, timing and slip control
In order to compensate for satellite drift and the influence of not using the same clock source at the originating end and the receiving end, buffering is required at the receiving end. The location of the buffer is determined by the configuration of each channel or circuit and the location of the transition from one clock to another. The amount of buffering required depends on the clock source, satellite delay variation, the allowed slip interval and the configuration of each specific channel or circuit. Normally, when IDR voice circuits are connected to analog terrestrial networks, buffering is not required to compensate for satellite transmission delay variations, but when IDR voice or data is connected to a synchronous digital terrestrial network, buffering is required.
16.1 Transmission Delay Variation
The amount of buffering is related to the transmission delay. When the INTELSAT satellite is used, the nominal delay tolerance is given in Table 6, which corresponds to the nominal satellite position keeping tolerance. When the selected satellite (except the INTELSATV satellite) is allowed to have an inclination of 3°, the delay parameters corresponding to the inclination exceeding the nominal range and maximum value are shown in Table 7. These information can also be used in conjunction with Table 9 to determine the amount of buffering for a specific link. 227
INTELSAT satellite
Maximum variation, ms
Maximum variation rate, ns/s
GB/T 11443.5-94
Table 6 Delay tolerance of INTELSAT satellite when maintaining nominal position1V
Note: ①Maximum variation: Peak-to-peak value of transmission plus reception. ②Maximum variation rate: transmission plus reception.
1) The delay tolerance depends on the orbit deviation listed in Table 8. VA
VA(IBS)
Table 7 Satellite delay parameters when INTELSATV, VA and VA(IBS) satellites are tilted more) Tilt, (°)
Maximum variation, ms
Maximum variation rate, ns/s
Note: ①Maximum variation: Peak-to-peak value of transmission plus reception. ②Maximum variation rate: transmission plus reception.
1) The delay tolerance depends on the orbit deviation listed in Table 8. VA
VA(IBS)
Table 7 Satellite delay parameters when INTELSATV, VA and VA(IBS) satellites are tilted more) Tilt, (°)
Maximum variation, ms
Maximum variation rate, ns/s
Note: ①Maximum variation: Peak-to-peak value of transmission plus reception. ②Maximum variation rate: transmission plus reception.
1) The east-west source drift will be kept within ten 0.1\. INTEISAT satellite
East-west drift (degrees)
South-north drift (degrees)
16.2 Timing accuracy
VA (IBS)
Bidirectional transmission of subgroup 2.048Mbit/s digital signals, the timing clock is recovered from one of the following three methods: a clock source with an accuracy of 1×10-1 in the digital network or a reference source that reaches the required accuracy (such as remote navigation-C). The remote earth station clock is received through the satellite, but the remote earth station clock must be restored in a way. b.
When there is no synchronous digital network at both ends and the channel is converted to an analog voice circuit, the internal clock of the PCM multiplexing equipment must have sufficient accuracy (about 50×106).
In addition, as an emergency backup, a local clock (with a long-term stability of at least 1×10-5/month in both cases a and b) is required to keep the circuit working when the main clock source fails. 16.3 Buffer Capacity
To obtain the appropriate buffer capacity, three examples of circuit arrangements are shown in Figures 13, 14, and 15. Table 9 is used to determine the approximate buffer capacity for each case. Figure 16 shows an example where no buffering is required. Table 9 Minimum capacity required for Doppler/quasi-synchronous buffer Satellite orbit inclination, ()
0.1(nominal)
Case 1 (Figure 13)
Buffer capacity for various circuit structures, ms Case 2 (Figure 14)
Case 3 (Figure 15)
Case 4 (Figure 16)
No buffer required
Satellite orbit inclination, (\)
Case (Figure 13)
GB/T 11443.5--94
Continued Table 9
Buffer capacity for various circuit structures, ms
Case 2 (Figure 14)
Case 3 (Figure 15)
Case 4 (Figure 16)
Note: ①) The minimum buffer capacity in the table includes two factors that allow the buffer to start from the center and then drift in any direction on both sides. ② The buffer capacity in the table is the sum of the requirements due to satellite delay variation (Doppler buffer) and different national clock interfaces (quasi-synchronous buffer).
③ Since the initial bit stream needs to slide on a multi-bit basis, the actual buffer capacity may be larger. a. Case 1: Any channel with independent digital networks at the transmitting and receiving ends. The timing signal is taken from 16.2 a with an accuracy of 1×10-\ clock, as shown in Figure 13. The slip interval is at least 70 days. b. Case 2: The timing applied to one end of the satellite link is the clock recovered from the demodulator. At the same time, this recovered clock is sent back to the original timing signal end, as shown in Figure 14.
Case 2: The timing used at one end of the satellite link is derived from the demodulator recovered clock. However, this recovered clock is returned to another earth station that is different from the initial clock, as shown in Figure 15. With a clock accuracy of 1×10-11 and the buffer capacity given in Table 9, the slip interval is at least 70 days. d. The fourth case: It is applied when there is no synchronous digital network at both ends of the link, and the receiving channel is converted to an analog voice channel, or each direction of transmission is limited to a separate point-to-point. In this case, no buffering is required, and the transmission timing is derived from the PCM channel bus, PCM/FDM transmission multiplexing equipment, digital terminal, or similar equipment that converts between analog and digital modes. The receiving timing is taken from the recovered clock of the demodulator, as shown in Figure 16. 16.4 Buffer position
In most cases, the receiving end completes the buffering at the primary group bit rate (2.048Mbit/s). For higher group carriers (8.448Mbit/s) is buffered after the multiplexing and demultiplexing equipment because the existing high-order group multiplexing equipment does not allow the use of an external clock source for timing. However, the above method can use a clock source with an accuracy of 1×10-11 to complete the buffering of high-order groups or sub-group rate data for bidirectional transmission. 16.5 Slip control
When the channel buffer control fails or reaches saturation or no load, the buffer should be reset. For the 2.048Mbit/s quasi-synchronous digital network, the slip is an integer multiple of the frame length. 17 Baseband characteristics
The performance characteristics of the IDR carrier can provide the transmission of any digital information: PCM coded telephone with or without DCME (using LRE/DSI), digital data, digital images or multiplexes of these services. The IDR carrier can be designed for single-address (SD) or multiple-address (MD) operation. This standard only considers single-address operation. 17.1 Single-site (SD) operation
The baseband characteristics of single-site operation should be equally applicable to future developments in multi-site operation. 17.2 Signaling
The arrangement of signaling, including the configuration of transmission paths and the selection of signaling systems, shall be determined by the participating organizations. 17.3 Voice channel interface
17.3.1 PCM encoding
In a 64kbit/s channel, the PCM of the analog voice channel uses A-law encoding. PCM multiplexing equipment complies with the provisions of GB7611. 17.3.2 Echo control
The voice circuit requires the installation of an echo canceller. The echo canceller shall comply with CCITT RecG165.229
17.4LRE/DSI interface
GB/T 11443.5-94
2.048Mbit/sLRE/DSI equipment and IDR channel unit complete the interface at the primary group rate of 2.048Mbit/s, and the IRE/DSI data stream passes through the IDR equipment transparently.
18Carrier activation and online monitoring
During carrier activation, equipment for link parameter measurement should be provided. When the equipment is initially activated, it should be able to meet the EIRP of the transmitting carrier, the Er/N of the receiving carrier. And the measurement of the bit error rate using a pseudo-random test code. It is recommended that the IDR equipment at least has the performance monitoring of E/N and BER during online communication. . kB
Normalized frequency, Hz
Figure 1 IF and RF amplitude response of earth station
Normalized frequency, Hz
Figure 2 IF and RF group delay response of earth station 230
GB/T11443.5—94
SSB phase noise density, dBc/Hz
Encoder
Away from center frequency, Hz
Figure 3 Requirements for continuous SSB phase noise
1/2 code Coded data of rate
Generator polynomial = 133 (octal)
3/4 code rate punctured coded data
Bit deletion formula -110
Bit selector
Bit selector
Generator polynomial 171 (octal)
Bit division formula ~11
Figure 4 Block diagram of the convolutional coding process for Viterbi decoding (3/4 code rate FEC) Note: ① Symbol A represents a modulo 2 adder. ② In the bit deletion formula, 1 represents transmission and 0 represents period division. ③ The rightmost stage of the shift register corresponds to the smallest effective bit Q in the polynomial
GB/T 11443.594
Device kill,
Group & Cargo
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