This standard specifies the baseband-to-baseband measurement methods for frequency division multiplexing (FDM) telephones. It is a supplement to GB11299.4 "Baseband Measurements" in this series of standards. The content of this section is applicable to both telephones and televisions, such as the amplitude/frequency characteristics of group delay. All the following measurements can be made on a loop established by a test repeater, including the transceiver link, or on an intermediate frequency self-loop. GB/T 11299.13-1989 Satellite communication earth station radio equipment measurement methods Part 3: Subsystem combined measurements Section 3: Measurement of frequency division multiplexing transmission GB/T11299.13-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods of measurement for radio equipment used in satellite earth stationsPart 3:Methods of mcasurements for combinations of suh-systemsSection Three-Measurements for FDM transmissionThis standard is the first of the series of standards "Methods of measurement for radio equipment used in satellite earth stations for satellite communicationSubject content and scope of application
GB11299.13---89
This standard specifies the baseband-to-baseband measurement methods for frequency division multiplexing (FDM) telephone. It is a supplement to GB11299.4\Baseband measurement\ in this series of standards. The content of this section is applicable to both telephone and television, such as group delay and amplitude/frequency characteristics. All the following measurements can be performed on the transmission loop established by the test transponder, including the transmit and receive links, or on the intermediate frequency self-loop. 2 Noise Loading Characteristics
2.1 Definitions and General Considerations
The noise loading characteristics of a system are the noise power measured in a selected narrowband measurement channel simulating an unloaded telephone line when a spectrally uniform random noise (white noise) is applied to the baseband input at a conventional load level (see 2.1.1). During the test, the white noise applied to the baseband input of the system under test is limited to the frequency band occupied by the telephone channel by high-pass and low-pass filters. Each noise measurement channel is provided with narrowband filters so that the characteristics can be measured at several frequency positions in the baseband frequency range including the low, mid and high end of the telephone line. In the noise measurement channel, the total noise presented to the system output consists of the fundamental noise and the intermodulation noise (sometimes called unloaded noise and distortion noise, respectively). In order to measure the total noise and fundamental noise separately, the common method is to load the baseband with noise in each noise measurement channel and then remove the noise load, and obtain the intermodulation noise from these measurement results. The noise characteristics of a system are expressed as noise power ratio (n.r.) or signal-to-noise ratio. The system zero relative level point is used as the reference noise power or noise power level. The unit of noise power is pW, and the unit of noise power is decibels above 1pW or fractions below 1mW, with specific indication of whether it is a weighted value. The noise power ratio is defined as the ratio of the noise power measured in the measurement channel when the baseband is fully loaded with white noise to the noise power measured when all basebands except the measured channel are loaded (i.e., total noise) or not loaded (i.e., basic noise). The noise power ratio is always expressed in positive decibels. The signal-to-noise ratio is defined as the ratio of the standard test tone power (Od13m()) to the noise power in the noise measurement channel within the specified bandwidth, both of which are referenced to the same point in the circuit. The signal-to-noise ratio can be measured under weighted or unweighted conditions and expressed in decibels. For the conversion of common noise load measurement units, please refer to Appendix A (reference). 2.1.1 Normal load
The normal load levels for certain typical numbers of voice channels defined by the International Telegraph and Telephone Consultative Committee (see Reference 1) and recommended by the International Radio Consultative Committee (see Reference 2) are shown in Table 1. The normal load average power level for other channel capacities is 1. The following formula can be used to calculate: L -- 15 + 10 logicN dBmO,N = 240 Approved by the Ministry of Electronics Industry of the People's Republic of China on March 1, 1989 130
++( 1
Implemented on January 1, 1990
Where: N--·—system channel capacity.
GB11299.13-89
1+4logioNdBmO,12≤N<240
Note: (1) These levels simulate the average power of voice plus signaling transmitted on the system during busy hours. If the baseband is mainly used for video, telegraph or data transmission, the above two formulas cannot be used.
②) When N=60, the levels given by (1) and (2) are very similar to the actual signal levels. However, for smaller channel capacities, due to the difference in the properties of the actual signal average and the test signal, the authenticity of the white noise test is lower. A conventional load system is a system that is loaded with a random noise signal with a uniform spectrum at a conventional load level. The bandwidth of the signal guide is limited to a system that is consistent with the total bandwidth of the frequency division multiplexing signal. In most cases, the test signal level is selected to be equal to the conventional load level. Table 1 Conventional load level
2.1.2 Noise components
Conventional load level (dBmo)
In the baseband of the simulated satellite system, the measured total noise includes the following three components: a.
Residual noise that is independent of path loss and load. This noise is usually called basic noise that is independent of path loss. Thermal noise that varies with path loss. This noise is usually called basic noise related to path loss. h.
c. Intermodulation noise related to the baseband noise load level. Basic noise a+b, as described in Section 2.3.4, is measured without adding noise load. Total noise a+b+c, as described in Section 2.3.2 or 2.3.3, is measured with noise load.
2.2 Measurement Equipment
·General Considerations
Noise load characteristic measurement equipment has been commercialized and is usually called "white noise tester" or "noise load tester". The noise tester includes a noise generator and a noise receiver, and the typical circuit structure is shown in Figure 1. In order to ensure the universality of the test equipment and have good measurement accuracy, the relevant performance of the white noise tester should comply with the provisions of the International Radio Consultative Committee or the International Telegraph and Telephone Consultative Committee (see References 2 or 3). Commercial white noise testers usually have sufficient accuracy for measuring simulated satellite systems, and the error of the test equipment does not need to be considered. However, when the required measurement accuracy is comparable to the inherent accuracy of the test equipment, the measurement error should be considered in the expression of the measurement results. The measurement accuracy is related to many factors:
a. The accuracy of the attenuator and indicator of the generator and receiver; b. The number of band-stop filters inserted and the equivalent bandwidth of the noise measurement channel; c. The part of the load curve where the measurement is made, that is, whether the basic noise or the five-tone noise is dominant; d. The order of magnitude of the distortion that is dominant in the system under test. These factors are discussed in references (6) and (4) of this standard. 2.2.2 Noise generator
2.2.2.1 Output characteristics
When measuring at a bandwidth of about 2kHz, the voltage root mean square value of the noise source should not vary by more than ±0.5dB within the corresponding baseband bandwidth of the system under test; a test signal with a Gaussian amplitude distribution should be used, with a peak-to-root mean square ratio of at least 12dB, and the minimum value of the generator output noise power spectral density not less than -40dB/kHz to ensure that the load level is at least 10dB higher than the normal load level used. The output level can be adjusted to the required value continuously or in smaller steps (e.g. 0.1dB) using the output attenuator. The attenuation range of the attenuator is generally more than 50dB.
2.2.2.2 Band-limiting and band-stop filters High-pass and low-pass filters are required to limit the baseband frequency range of the system under test suitable for simulation. In order to determine the noise measurement channel, a series of band-stop filters are required. Universal white noise testers have a large number of filters that can test all common telephone channels. The recommended filter frequencies are shown in Table 2, and detailed filter characteristics are shown in Reference (2). 2.2.2.3 Insertion loss of band-stop filters
The bandwidth noise power output of the noise generator is generally required to be able to measure, and a power indicator is usually installed at the end of the filter chain (see Figure 1). The passband attenuation of the band-stop filter is usually a function of frequency, so an equalizer is often introduced to compensate for this change. When an equalizer is used, the total passband insertion loss is of the order of several decibels. After inserting the band-stop filter, the insertion loss should be compensated to restore the output level to the initial value. New noise generators have automatic level control and automatic correction. In some generators, the bandwidth power indicator is before the band-stop filter. The output level should be corrected according to the insertion loss reference table given in the instrument manual. Note: Although restoring the output power to the initial value will change the power spectral density of the signal, this effect can be ignored because the frequency band occupied by the band-stop filter is usually very narrow.
2.2.3 Noise Receiver
There are two different types of receivers in general applications. The first type is suitable for measuring noise power ratio. It includes a separate attenuator with a large enough attenuation range (for example, 0-80dB), which is directly connected to the receiver input (see 2.3.2); the second type is suitable for measuring the noise power based on the system zero relative level point, in units of pWOp or dBmOp, and is generally used in combination with two attenuators: the first is calibrated for the transmission level (dBr), and the second is an attenuator with 10dB steps combined with a meter for reading (see 2.3.3). Regardless of which receiver is used, when the white noise load level is directly added to more than 10dB higher than the normal load level and the relative level is -15dBr, the design of the amplifier, mixer and attenuator should avoid saturation or excessive nonlinearity. For a 972-channel system, this is equivalent to a receiver input level of up to about 10dBm. In order to measure the noise power of a large capacity system with a load level 10 dB below the normal load level, the local noise of the receiver should be less than -125 dBmp.
The equivalent bandwidth of the receiver should be not less than 1.7 kHz. In order to make it narrower than the bandwidth of the band stop filter of 70 dB, it should not exceed 2.5 kHz.
GB11299.13--89
Requires that the band pass filter and the center frequency of the noise generator band stop filter are consistent. The selectivity of these filters should be good enough to prevent the receiver amplifier (or mixer) from overloading or spurious response. 2.2.4 Intrinsic intermodulation of white noise tester
When the noise generator is connected to the noise receiver and the generator output noise power level is equal to the normal load level (Table 1), the total noise in any measurement channel should make the noise power ratio at least 67 dB. For N = 240, the corresponding noise power level value is 85. 9 clBmOp.
Capacity (number of voice channels)
2.3 Measurement method
Frequency occupied by telephone channels
Range, kHz
12~~60
12-~108
12~156
12~204
12~252
12~300
12~408
12~552
12~804
121052
12~1300
12~1796
12~2 540
12~~3 284
12~4028
12~4892
12~-5 884
12~8120
12~~1548
12~2044
12~2 292
2.3.1 Input noise level
Recommended filter frequency (see Reference 2) Effective cut-off frequency of band-limited filter, kH2 High
12 ± 0. 5
12 +- 0. 5
1 296±8.0
179612
2600±20
3284+25
4100+30
4 892+40
5884+50
8 160+75
1548±10
2 04414
2292±17
Recommended measurement channel frequency.kHz
5311002
5341248
534 1002 1730
770 1730 2 438
100224383150
1002 2438 3886
1 002 2 438 4 650
1002315046505310
1002315053407600
534 1002 1490
534 1248 1940
770 1 730 2 150
Connect the noise generator to the baseband input of the system under test. Select appropriate high-pass and low-pass filters to limit the noise bandwidth to the bandwidth of the system baseband. The normal load level is calculated using (1) or (2), or selected from Table 1. The noise power added to the baseband input terminal A can be obtained by adding the normal load voltage to the relative power level at point A. For a certain system capacity, for example 1872 channels, when the baseband input relative level is 37dBr, the noise generator output level (Lou) is: Laut—15+-10logle(1872)(dBmO)-37dBr - --19.3dBm2.3.2 Method of indicating noise power ratio of noise-city receiver (3)
Connect the noise generator and noise receiver to the baseband input and output of the system under test respectively, and select the noise measurement channel. The band-stop filter of the generator is not connected to the circuit. The system input noise level is adjusted to the normal level or other specified level. The receiver attenuator is connected to the receiver meter to show a given reference reading. Then an appropriate band-stop filter is connected to the circuit. If necessary (see 2.2.2.3), the level of the generator is restored. This can reduce the attenuation of the receiver until the reference reading is regained. The noise power ratio is the difference between the two set readings of the receiver attenuator. The conversion of noise power ratio to other noise load units is described in Appendix A. 2.3.3 Method of indicating noise power or signal-to-noise ratio by noise receiver Connect the noise generator and noise receiver to the baseband input and output of the system under test respectively. Select Determine the latent sound measurement channel and capture the appropriate band-stop filter. The system input noise level is adjusted to the normal level or other specified level. If necessary (see Section 2.2.2.3), a tolerance should be specified for the insertion loss of the filter. The receiver transmission level attenuator is adjusted to a value that is suitable for the relative level of the system baseband output, and then the range reducer is changed to increase the sensitivity until a reading is obtained on the receiver meter: if possible, this reading should be in the appropriate indication area of ​​the meter. The sum of the readings of the range attenuator and the meter directly gives the noise power referenced to the zero relative level point of the system. 2.3.4 Basic noise
Measurement of basic noise should be read when there is no noise load. This is very convenient to measure with a noise on/off switch on a new noise generator. This switch can suppress noise output, while keeping the generator output impedance unchanged. A receiver calibrated with noise power or level gives a first-connection reading of the basic noise.
A receiver calibrated with noise power ratio needs to be measured relative to the lower reference level, as described in 2.3.2. The resulting noise power ratio can be expressed as a basic noise power ratio, or converted to a noise power level using the method in Appendix A. 2.3.5 The total noise is a function of the noise load level and the received RF carrier level. In accordance with 2.3.2 (regarding noise power ratio) or 2.3.3 (regarding noise power or signal-to-noise ratio), the total noise can be measured within a certain range (for example -6 to +10 dB) between the relative value of the noise load level and the normal load level, and a curve as shown in Figure 2 or Figure 3 can be drawn (depending on the selected noise Unit of measurement). When the white noise load increases above the rated or normal value, the noise is similar to intermodulation noise, which is closely related to the load; when the self-noise load is reduced to below the normal value, the noise is similar to basic noise and is independent of the load. The measurement is generally carried out under the condition that the received RF carrier level is adjusted to the rated value, but if the noise load characteristics are highly dependent on this level, the noise load measurement is often repeated at several lower RF carrier levels. For each received RF carrier level, a noise curve similar to that shown in Figure 2 or Figure 3 can be made over the entire range of noise load levels.
2.3.6 Changes in noise power ratio with input level This measurement shows the effect of level imbalance along the transmission path or the change in performance at different frequency offsets. It is measured using the measurement equipment in Figure 1 and the additional measurement device in Figure 4. The steps are as follows: a. Adjust the noise load power level at point A to the specified value and keep it unchanged. b. Change the attenuator -△L and +△L in a sufficiently large range, and the attenuation changes caused by -△ and +L are always of equal absolute value.
c. The noise power ratio or channel noise level is measured as a function of the level at point A'. The results are plotted as shown in Figure 2.4. Result presentation
When the measurement is required for a few received RF carriers and/or load levels, the results shall be presented in a table showing the received RF carrier levels, the frequencies of the noise measurement channels, etc., as well as the basic noise measurement values ​​and the total noise measurement values. When the measurement is required for a certain range of received RF carriers and/or load levels, the values ​​shall be presented in a graph similar to that shown in Figure 2 or Figure 3. 2.5. Details to be specified
When this measurement is required, the following shall be included in the equipment specifications: 2. Baseband channel capacity;
b. Cut-off frequency of high-pass and low-pass filters, kHz; 13.4
Pre-emphasis/de-emphasis characteristics;
Relative level at baseband input.dBr:
Normal load level dBmO;
GB11299.13--89
Noise load level range relative to normal load.dIB; RMS frequency deviation (test audio deviation) of each voice channel, kHz: Relative level at baseband output, dBr;
Noise measurement channel heart frequency, kHz;
Range of received RF carrier level;
Tolerance of basic noise level;
Tolerance of total noise level.
3 Continuous pilot and out-of-band noise
General considerations
In satellite communication systems, continuous pilots and baseband noise performance in suitable frequency slots outside the communication band are usually checked regularly without interrupting service. This allows continuous evaluation of system performance without interrupting service. Out-of-band noise measurements can also be used in acceptance tests to obtain a reference value that can be compared with the test value when there is service. 3.2 Measurement method
The measurement method is similar to the in-band measurement method. However, only the method described in Section 2.3.3 can be used. In order to select the out-of-band noise measurement frequency and pilot, a frequency-selective level meter is used instead of a white noise receiver. The bandwidth of the frequency-selective level meter must be smaller than the bandwidth of the band-stop filter inserted into the transmission channel. An example of an equipment configuration for measuring out-of-band noise is shown in Figure 5. The recommended frequencies are listed in Table 3. Detailed filter specifications are given in Reference (5). Usually the band-stop filter is included in the baseband section of the frequency modulator.
If the white noise tester is not equipped with a transmission band-stop filter for out-of-band noise measurement, then a suitable band-stop filter needs to be inserted between the output of the white noise generator and the input of the system under test. Table 3
System capacity
(number of voice channels)
Frequency band occupied by telephone channels
12~108
12~156
12~204
12~252
12-300
12~408
12~552
12~804
12~1052
12~1300
12-1548
12-1796
Center frequency of the noise measurement frequency slot?
System capacity
(number of voice channels)
Measurement is carried out according to the following steps:
GB11299.13-89
Continued Table 3
Frequency band occupied by telephone channels
12~2 044
12～2 292
12~2 540
12~3 284
12-~4 028
12~4 892
12~~5884
12~8120
Center frequency of noise measurement slot!
a. Disconnect the white noise load, tune the frequency-selective level meter to the frequency of the continuous pilot, and record the pilot level. If necessary, adjust the system under test so that the continuous pilot at its baseband output reaches the rated level. b. Add a white noise load, tune the frequency-selective level meter to the frequency of the out-of-band noise bin, and record the power level of the out-of-band noise bin. 3.3 Result Representation
The out-of-band noise can be expressed as an absolute value with a zero relative level point as a reference (e.g. -68dBmO), or as a ratio of the continuous pilot signal to the out-of-band noise (e.g. 43dB). In either case, the equivalent noise bandwidth of the out-of-band noise bin must be specified (e.g. 1.74kHz or 3.1kHz). If the frequency-selective level meter bandwidth is different from the specified bandwidth, the measured noise power should be appropriately corrected. 3.4 Details to be specified
When this measurement is required, the following shall be included in the equipment specifications: a.
Capacity of the baseband channel;
Pre-emphasis characteristics;
Relative level at the baseband input, dBr;
Normal load level, dBmO;
Relative level at the baseband output, dBr;
Frequency of the out-of-band noise bin;
Frequency and level of the continuous pilot;
Tolerance of the noise level of the out-of-band noise bin at the rated load level. 4 Periodic noise
4.1 General considerations
Periodic noise is mainly caused by power supply ripple and baseband spurious signals, which include harmonics and possible energy diffusion waveforms.
4.2 Measurement method
Measurements should be made over the entire baseband using a spectrum analyzer or a frequency-selective level meter under the conditions of baseband no-load and baseband output matching. 4.3 Result presentation
The result should be expressed in dBmO.
4.4 Details to be specified
When this measurement is required, the equipment specifications should include the following: tolerance of periodic noise level;
b, baseband frequency range.
5 Intelligible crosstalk
5.1 Definition and general considerations
GB11299.13-89
Crosstalk is defined as the transfer of useless energy from an "interfering" circuit to another "interfered" circuit. If the transferred energy contains intelligible information, this phenomenon is called "intelligible crosstalk". The intelligible crosstalk ratio is expressed as the ratio of the useful signal in the interfered channel to the unwanted signal power caused by the signal from the interfered channel in the interfered channel.
Intelligible crosstalk between two satellite communication circuits can occur at any section of the transmission or reception path. For example, in a multi-carrier transmission path, when a network exhibiting amplitude modulation/phase modulation conversion is connected in series with a network exhibiting nonlinear amplitude/frequency characteristics, intelligible crosstalk may be introduced. 5.2 Measurement method
When measuring the intelligible crosstalk ratio, the interfering channel and the interfered channel are loaded with bandwidth-limited random noise generated by respective white noise generators to simulate the working conditions. The measurement equipment configuration is shown in Figure 6. The same band-stop filter is inserted into the output of each noise generator to generate a narrow noise-free band with the same center frequency in the interfering channel and the interfered channel. A sinusoidal single-tone signal with a frequency of the noise-free center frequency is added to the interfering baseband channel, and the signal level at the noise-free center frequency appearing in the interfered baseband channel is measured using a frequency-selective level meter or a spectrum analyzer to measure the size of the crosstalk ratio. In order to evaluate the total contribution of all subsystems, it is recommended to establish an RF loop using an RF attenuator connected to the output of the high power amplifier, through a standard repeater or test repeater, and to the input of the low noise amplifier, as shown in Figure 6. Both the interference channel and the disturbed channel should include all subsystems between the baseband ports. Before starting the measurement, it must be verified that each subsystem is correctly adjusted to the specified operating values ​​(it is particularly important to ensure that the sensitivity of the modulator and demodulator, the output power of the high power amplifier and the input power level of the low noise amplifier are correctly adjusted). Referring to Figure 6, the measurement steps are as follows:
. Select appropriate band-limiting filters and insert two identical band-stop filters, and adjust the gate noise generators of 1 (interfered channel) and 2 (interfering channel) to the required load level. b. Connect the interfering channel adder 2 to the standard terminal load (switch S.), connect the sinusoidal test signal generator to the interfered channel adder 1 (switch S), and adjust the sinusoidal signal to the center frequency (f) of the noise-free band, and adjust the level to its specified value (for example, OdBmO). C. Under the condition that the frequency-selective level meter or spectrum analyzer is connected to the baseband output of the interfered channel, measure the level of the sine test signal with a frequency of , which is the reference level. d. Connect the standard terminal load to the adder 1 (switch S,) of the interfered channel. Connect the sine test signal to the adder 2 (switch S,) of the interfering channel, and re-measure the test signal level. The ratio of the reference level measured in step c to the test signal level is the crosstalk ratio.
e Repeat steps a to d within the specified range of the sine test signal level. 5.3. Presentation of results
The results may be presented as a copy of the baseband spectrum analyser display, in a table or as follows: "For the following sinusoidal test signals in the range 0 to -15 dBmO, the intelligible crosstalk ratio is better than .dB". 5.4. Details to be specified
When this measurement is required, the equipment specifications shall include the following: a. The RF channel used and the baseband tolerances of the interfering and interfered channels; h. The centre frequency f of the noise-free band; c. The level range of the sinusoidal test signal; d. The tolerance for the minimum intelligible crosstalk ratio.
6 References
(1) CCITT,Recommendation G.223:137
GB 11299.13--- 89
means of asignal of uniform spectrum for systems using frequency division multiplex telephony in thcfixed satellite service.
(3) CCITT,Recommendation G. 228: Measurement of circuit noise in cable systems using a uniform spectrum random noise loading.CCITT ,Recommendation G. 228: (4) (
Annex1andAnnex2.
CCIR ,Recommendation 481--1(Vol.IV):(5)
Measurement of noise in actual traffic forsystems in the fixed-satellite service fortelphony using frequency—division multiplex.138
installed in the year
by the system under test
high-pass filter
noise source
equivalent bandwidth B
variable attenuator
GB11299.13-89
low-pass filter
output the whole system under test:
test signal power level L
noise generator
band-pass filter
automatic level control
band-stop filter
frequency-selective amplifier
mixer
local oscillator
noise receiver
Figure 1 schematic diagram of white noise tester
variable attenuator
variable attenuator
GB 11299. 13--89
Relative value of input white noise load level to rated
level (dB)
Example of noise performance as a function of load: Noise power ratio measurement60
（o）
Relative value of input white noise load level to rated
level (dB)
Example of noise performance as a function of load: Noise power level or weighted signal-to-noise ratio measurementA
Attenuatorwww.bzxz.net
Attenuator
Figure 4 Typical equipment configuration for measuring changes in system noise power ratio1--Transmitter part of noise tester (see Figure 1); 2-System under test; 3-Receiver part of white noise tester (see Figure 1)Download
Self-noise generator1
(interfered band)
Sine test
Signal generator
Gate noise generator 2
(Ten-band)
with lazy harmonic analyzer
or frequency-selective electronic meter
white noise tester
GB11299.13—89
continuous pilot
system under test
frequency-selective electronic meter
equipment configuration for measuring out-of-band noise and continuous pilot level modulator 1
modulator 2
demodulator 1|| tt||Demodulator 2
[:Converter 1
Upconverter 2
Downconverter 1
Downconverter 2
High power amplifier
Low noise amplifier
Figure 6 Equipment configuration for measuring intelligible crosstalk ratio
Download
Attenuator
High power
Standard repeater
Or test repeater13--89
Relative value of input white noise load level to rated
level (dB)
Example of noise performance as a function of load: Noise power ratio measurement60
（o）
Relative value of input white noise load level to rated
level (dB)
Example of noise performance as a function of load: Noise power level or weighted signal-to-noise ratio measurementA
Attenuator
Attenuator
Figure 4 Typical equipment configuration for measuring changes in system noise power ratio1--Transmitter part of noise tester (see Figure 1); 2-System under test; 3-Receiver part of white noise tester (see Figure 1)Download
Self-noise generator1
(interfered band)
Sine test
Signal generator
Gate noise generator 2
(Ten-band)
with lazy harmonic analyzer
or frequency-selective electronic meter
white noise tester
GB11299.13—89
continuous pilot
system under test
frequency-selective electronic meter
equipment configuration for measuring out-of-band noise and continuous pilot level modulator 1
modulator 2
demodulator 1|| tt||Demodulator 2
[:Converter 1
Upconverter 2
Downconverter 1
Downconverter 2
High power amplifier
Low noise amplifier
Figure 6 Equipment configuration for measuring intelligible crosstalk ratio
Download
Attenuator
High power
Standard repeater
Or test repeater13--89
Relative value of input white noise load level to rated
level (dB)
Example of noise performance as a function of load: Noise power ratio measurement60
（o）
Relative value of input white noise load level to rated
level (dB)
Example of noise performance as a function of load: Noise power level or weighted signal-to-noise ratio measurementA
Attenuator
Attenuator
Figure 4 Typical equipment configuration for measuring changes in system noise power ratio1--Transmitter part of noise tester (see Figure 1); 2-System under test; 3-Receiver part of white noise tester (see Figure 1)Download
Self-noise generator1
(interfered band)
Sine test
Signal generator
Gate noise generator 2
(Ten-band)
with lazy harmonic analyzer
or frequency-selective electronic meter
white noise tester
GB11299.13—89
continuous pilot
system under test
frequency-selective electronic meter
equipment configuration for measuring out-of-band noise and continuous pilot level modulator 1
modulator 2
demodulator 1|| tt||Demodulator 2
[:Converter 1
Upconverter 2
Downconverter 1
Downconverter 2
High power amplifier
Low noise amplifier
Figure 6 Equipment configuration for measuring intelligible crosstalk ratio
Download
Attenuator
High power
Standard repeater
Or test repeater
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