GB/T 11318.13-1996 Cable distribution system equipment and components for television and sound signals Part 13: General specification for receiver converters
Some standard content:
1 Scope
National Standard of the People's Republic of China
Equipment and components used in cabled distribution systems for television and sound signals
Part 13: Generic specifications for set top converter Equipment and components used in cabled distribution systems primarily intended for television and sound signals Part 13: Generic specifications for set top converter GB/T11318.13—1996
This standard specifies the requirements, test methods, inspection rules, marking, packaging, transportation and storage of receiver converters (hereinafter referred to as converters) in cabled distribution systems for television and sound signals of 5MHz~1750MHz. This standard applies to receiver converters in cabled distribution systems for television and sound signals of 5MHz~1750MHz. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference 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. GB/T6510—1996 Cable distribution system for sound and television signals GB/T11318.1-1996 Cable distribution system for television and sound signals Equipment and components Part 1: General specifications 3 Definitions
This standard adopts the following definitions, and other definitions should comply with the relevant provisions in GB/T11318.1 3.1 Adjacent channel carrier rejection The converter's ability to suppress the upper adjacent channel image carrier and the lower adjacent channel sound carrier of the working channel, the ratio of the output working channel image carrier level to the upper adjacent channel image carrier level and the lower adjacent channel sound carrier level, respectively, takes the smaller value, expressed in decibels. 3.2 Input to output isolation The attenuation of the input channel through-signal at the output end of the converter, expressed in decibels. 3.3 Input beats rejection ratio The beat signals generated by the image carrier of all channels and other frequency components in the first frequency converter within the working frequency range are reversely transmitted to the input end and fall within the working frequency range. The ratio of the input working channel image carrier signal level to the beat signal level is taken, expressed in decibels. 3.4 Frequency drift frequency drift
Under the extreme working temperature, the difference between the output signal frequency of the converter and the initial value at 20℃ is taken as the maximum value. 4 Product classification
Converters can be divided into two categories according to their signal processing methods: Approved by the State Administration of Technical Supervision on September 9, 1996 and implemented on May 1, 1997
GB/T11318.13-1996
a) Class I converter (Class IA converter, Class IB converter), that is, up/down conversion converter; b) Class II converter, that is, up/down conversion demodulation-modulation converter. 5 Requirements
5.1 General requirements
The general requirements for converters shall comply with the requirements of 4.1.1 of GB/T11318.1-1996. 5.2 Performance Parameters
The performance parameter requirements of the converter are shown in Table 1 and Table 2. Table 1 Performance Parameter Requirements of Class-A Converter
Operating Frequency Range
Maximum Channel Capacity
Output Channel
Input Level Range
Input and Output Impedance
Input Reflection Loss
Output Reflection Loss
Automatic Gain Control Start Level
Intra-Band Fluctuation
Adjacent Channel Carrier Suppression
Input and Output Isolation
Input Beat Suppression Ratio
Noise Figure
Cross-Interference Modulation Ratio
Carrier Combination Second-Order Beat Ratio
Carrier Combination Third-Order Beat Ratio
Input First Local Oscillator Signal Leakage Level
Input Parasitic Signal Level:
5 MHz~-30 MHz
48 MHz~550 MHz
Output second local oscillator signal leakage level
Spurious output suppression
Frequency accuracy
Frequency shift
TV channel configuration see Appendix A (Standard Appendix). 1
2Gain is measured at the image carrier point, input level is 60d13μV. 404
Performance parameters
dBμuv
48~550
DS1 or DS2
75 (unbalanced)
≥>57
50(≤1GHz）
≤55(>1 GHz)
Operating rate range
Maximum channel capacity
Output channel:
Input level range
Input and output impedance
Input end reflection loss
Output end reflection loss:
Input level
Output level
Input and output impedance
Input level
Output level
Input and output impedance
Image carrier output level
Image/companion Audio-to-carrier power ratio
Frequency accuracy
Frequency drift
Image-to-sound carrier frequency spacing
Combined intermodulation
Carrier combination second-order beat ratio
Carrier combination third-order beat ratio
Input beat suppression ratio
Spurious output suppression
Video signal modulation
Maximum frequency deviation
Color/luminance delay difference
Color/luminance gain difference
Audio frequency band flatness
GB/T 11318.13-1996
Performance parameter requirements of Class II converters
V (peak value)
V (peak-to-peak value)
V (rms)
Performance parameters
48~550
DS1 or DS2
DS24~DS26
75 (unbalanced)
1.0 (positive polarity)
1.0 (positive polarity)
6~+6(600 )
≥0.2(47ko load)
600(balanced/unbalanced)
6500±20
≥>57
75±10
Flatness in video band
Video signal-to-noise ratio
Differential gain
Differential phase
Audio distortion
Audio signal-to-noise ratio
GB/T 11318.13—1996
Table 2 (end)
See Appendix A (Standard Appendix) for TV channel frequency configuration. 2 Flatness in video band refers to the index within the bandwidth of 0 MHz to 5 MHz. 3 Video signal-to-noise ratio is a weighted index.
Performance parameters
RF input
RF output
4 Flatness in the audio band refers to the index measured with 1kHz as the reference point within the range of 100 Hz to 10kHz. 5 Audio distortion is an index within the range of 1kHz. 5.3 Environmental adaptability
The environmental adaptability requirements of the converter shall comply with the relevant provisions of 4.3 in GB/T11318.1-1996. 5.3.1 Intermediate test
RF input
Baseband output
The intermediate test item of Class I converter is gain, and the test result should not vary by more than ±3dB relative to the initial test value. The intermediate test item of Class I converter is image carrier output level, and the test result should not vary by more than ±3dB relative to the initial test value. 5.3.2 Test items after high temperature, constant humidity, swept frequency vibration and collision test The test item of Class I converter is gain.
The test items for Class 1 converters are the image carrier output level and video signal modulation. 5.3.3 After the low temperature and free drop tests, the test items specified in 5.2 shall be carried out, and the test results shall comply with the relevant provisions. 5.4 Reliability
The lower limit of the mean time between failures (MTBF) of the converter shall not be less than 20,000 hours. The failure criterion is that the image carrier output level varies by more than ±6dB compared with the initial data, or the accompanying sound is abnormal. 5.5 Safety
The safety requirements of the converter shall comply with the relevant provisions of 4.5 in GB/T11318.1-1996. 5.6 Electromagnetic compatibility
The electromagnetic compatibility requirements of the converter shall comply with the relevant provisions of 4.6 of GB/T11318.1-1996. 6 Test methods
6.1 General requirements
The inspection method of the general requirements of the converter shall be carried out in accordance with the provisions of 4.1.2 of GB/T11318.1-1996. 6.2 Performance parameters
The relevant measurement provisions shall comply with the requirements of 4.2.2 of GB/T11318.1-1996. If there are no special provisions, the measurement of the converter performance parameters shall be carried out on the specified channels within the working frequency range. The specified channels are composed of every 5 channels, the highest and the lowest channels within the working frequency range. 406
GB/T 11318.13--1996
6.2.1 Automatic gain control start level, input and output isolation, second local oscillator signal leakage level, parasitic output suppression. 6.2.1.1 Measurement block diagram
As shown in Figure 1.
RF signal generator
Converter under test
Radio amplifier
Spectrum analyzer
Figure 1 Connection of automatic gain control start-up level, input-output isolation, second local oscillator signal leakage level, parasitic output suppression measurement equipment 6.2.1.2 Measurement
6.2.1.2.1 Automatic gain control start-up level measurement is carried out on three channels DS1, Z12 and DS22. Adjust the output frequency of the signal generator to the image carrier frequency (f,) of the specified channel, and the converter under test works on the specified channel. Adjust the output level of the signal generator so that the input level of the converter under test is 75dBμV, record the output level of the converter under test at this time, monitor the output level of the converter under test with a spectrum analyzer, and gradually reduce the output level of the signal generator. When the output level of the converter drops by 1dB, read the input level of the converter at this time, which is the automatic gain control start-up level. 6.2.1.2.2 Input-output isolation
Adjust the converter under test so that its input and output are in the same channel. Adjust the output frequency of the signal generator to the nominal image carrier frequency of the working channel, so that the input level of the converter under test is 75dBuV. Stop the second local oscillator of the converter under test or fine-tune the first local oscillator frequency to deviate from the nominal frequency point, and measure the through signal level of the working channel at the output end of the converter under test, and its value is recorded as A (dBμV). Input-output isolation is expressed in decibels: 75A (dB). 6.2.1.2.3 Second local oscillator signal leakage level Use a spectrum analyzer to directly measure the fundamental wave level value of the second local oscillator at the output end of the converter under test. 6.2.1.2.4 Parasitic output suppression
Adjust the RF signal generator so that the output frequency of the converter under test is the nominal image carrier frequency of the specified channel, and the input level is 75dBμV. The converter under test works on the specified channel. The output image carrier level of the converter under test and the parasitic products in the output channel (f.-1.25MHz~f.+6.75MHz) are measured by a spectrum analyzer. The minimum value of the difference between the levels is the parasitic output suppression. 6.2.2 In-band fluctuation, adjacent channel carrier suppression 6.2.2.1 Measurement block diagram
As shown in Figure 2.
Sweep signal generator
6.2.2.2 Measurement
6.2.2.2.1 In-band fluctuation
Variable attenuator
Converter under test
Detector
Figure 2 Connection display of in-band fluctuation, adjacent channel carrier suppression measurement equipment
The converter under test works on the specified channel, and the input level is 60dBuV. Adjust the sweep signal generator, attenuator and display so that the display shows a clear curve with appropriate amplitude. Measure the difference between the maximum and minimum amplitudes between f1 (sound carrier frequency), which is the in-band fluctuation, expressed in decibels.
6.2.2.2.2 Adjacent channel carrier suppression
The converter under test works on the specified channel with an input level of 60dBμV. Adjust the sweep signal generator, attenuator and display so that the display shows a clear curve with appropriate amplitude. Measure the level difference between f1+8MHz and f1-1.5MHz and f2 respectively. The smaller value is the adjacent channel carrier suppression, expressed in decibels. 407
6.2.3 Input Beat Suppression Ratio
6.2.3.1 Measurement Block Diagram
As shown in Figure 3,
Multi-channel signal generator
GB/T 11318.13-1996
Converter under test
Spectrum analyzer
Figure 3 Connection of input beat suppression ratio measurement equipment6.2.3.2 Measurement
Broadband terminal
The number of channels of the multi-channel signal generator is the maximum channel capacity of the converter under test. Adjust the output level of the signal generator so that the input level of each channel of the converter under test is 75dBμuV. The converter under test works on the specified channel, and the beat component transmitted backward to the input end is measured by the spectrum analyzer within the working frequency range. Take its maximum value, which is recorded as A (dBμV).
The input beat suppression ratio is expressed in decibels as: 75—A+B (dB)
Wherein: B is the insertion loss between ports 2 and 3 of the directional coupler. 6.2.4 Leakage level of the first local oscillator signal at the input end and the level of the parasitic signal at the input end 6.2.4.1 The measurement block diagram
is shown in Figure 4.
Spectrum analyzer
Converter under test
Figure 4 Connection of the measurement equipment for the leakage level of the first local oscillator signal at the input end and the level of the parasitic signal at the input end
6.2.4.2 Measurement
The converter under test works on the specified channel, and the spectrum analyzer is used to measure the leakage level of the first local oscillator signal fundamental wave in the frequency bands less than or equal to 1 GHz and greater than 1 GHz, and the maximum value of the parasitic signal level in the frequency bands of 5MHz~30MHz and 48MHz~550MHz is measured respectively.
6.2.5 Frequency drift
According to the frequency accuracy measurement method specified in 4.2.2.2.7 of GB/T11318.1-1996, at the reference temperature of 20℃, measure the image carrier frequency f of the output channel of the measured converter. According to the total frequency deviation measurement method specified in 4.2.2.2.7 of GB/T11318.1-1996, after being kept constant at the upper and lower limits of the specified working environment temperature (20±30)℃ for 1h, measure the image carrier frequency of the output channel of the measured converter respectively, and take the maximum value of the difference between it and f., which is the frequency drift.
6.2.6 Video signal modulation degree and maximum frequency deviation 6.2.6.1 Measurement block diagram
As shown in Figure 5.
Video signal generator
Audio signal generator
6.2.6.2 Measurement
GB/T11318.13—1996
Converter under test
Standard modulator
Figure 5 Connection of video signal modulation and maximum frequency deviation measurement equipment Measurements are performed on three channels: DS1, Z12 and DS22. Standard demodulator
The video signal generator generates a 1V (peak-to-peak) step full TV signal, and the audio signal generator generates a 0.775V, 1kHz sine wave. The video signal modulation of the standard modulator is 87.5%, the frequency deviation of the audio signal is 50kHz, and the output channel is the specified channel under test. The converter under test works on the specified channel under test, and the input level is 75dBμV. The video signal modulation and maximum frequency deviation are demodulated by a standard TV demodulator.
6.2.7 Flatness in the visual band
6.2.7.1 The measurement block diagram
is shown in Figure 6.
Video output
Converter under test
Video signal generator
6.2.7.2 Measurement
Standard modulator
Radio output
Standard demodulator
Figure 6. Connection of the equipment for measuring flatness in the visual band The measurement is carried out on three channels: DS1, DS12 and DS22. %s
Oscilloscope
The video signal generator generates a multi-burst or swept frequency signal with an amplitude of 420mV (peak-to-peak value). This video signal is modulated to the specified channel by a standard modulator. The converter under test works on the specified channel under test with an input level of 75dBμV. When switch S is connected to the video output of the standard demodulator, the video band flatness between the RF input and the RF output is measured with an oscilloscope; when switch S is connected to the video output of the converter under test, the video band flatness between the video input and the video output is measured with an oscilloscope. The video band flatness is measured in the frequency range of 0 MHz to 5 MHz. 6.2.8 Video signal-to-noise ratio
6.2.8.1 Measurement block diagram
As shown in Figure 7.
Video signal generator
Audio signal generator
6.2.8.2 Measurement
Standard modulator
GB/T 11318.13—1996
Video output
Converter under test
RF output
Standard demodulator
Figure 7 Connection of video signal-to-noise ratio measurement equipment
Visual noise
Measurement instrument
The video signal generator generates a 50% grayscale video signal (or a video signal specified by the video noise measurement instrument), and the audio signal generator generates a 1kHz, 0.775.V audio signal. The video signal and audio signal are modulated to the specified channel by the standard modulator. The converter under test works on the specified channel with an input level of 66dBμV. When the switch S is connected to the video output terminal of the standard demodulator, the video signal-to-noise ratio between the RF input and the RF output is measured by the video noise measurement instrument. When the switch S is connected to the video output of the converter under test, the video signal-to-noise ratio between the RF input and the video output is measured with a video noise meter.
6.2.9 Differential gain and differential phase
The measurement is carried out on the three channels DS1, Z12 and DS22. The measurement method is in accordance with the provisions of Chapter 12 of GB/T6510-1996. When the oscilloscope (or differential phase test device) is connected to the RF output of the converter under test through a standard demodulator, the differential gain (or differential phase) between the RF input/RF output is measured with the oscilloscope (or differential phase test device). When the oscilloscope (or differential phase test device) is directly connected to the video output of the converter under test, the differential gain (or differential phase) between the RF input/video output can be measured with the oscilloscope (or differential phase test device). 6.2.10 The chroma/luminance delay difference and chroma/luminance gain difference are measured on the three channels DS1, Z12 and DS22. The measurement method is in accordance with the provisions of Chapter 6 of GB/T6510-1996. When the delay difference (or gain difference) tester is connected to the RF output terminal of the converter under test via a standard demodulator, the chroma/luminance delay difference (or chroma/luminance gain) between the RF input and RF output is measured by the delay difference (or gain difference) tester. When the delay difference (or gain difference) tester is directly connected to the video output terminal of the converter under test, the color/luminance delay difference (or color/luminance gain difference) between the RF input and video output is measured by the delay difference (or gain difference) tester and an oscilloscope. 6.2.11 Flatness in the audio band and audio signal-to-noise ratio 6.2.11.1 The measurement block diagram is shown in Figure 8.
Audio signal generator
Video signal generator
6.2.11.2 Measurement
Standard modulator
GB/T11318.13—1996
Audio output
Converter under test
RF output
Standard demodulator
Figure 8 Connection of audio band flatness and audio signal-to-noise ratio measurement equipment The measurement is carried out on three channels DS1Z12 and DS22. s
Millivoltmeter
The audio signal is modulated to the specified channel by the standard modulator. The converter under test works on the specified channel with an input level of 75 dBμV.
In the specified frequency range (100Hz～10kHz), a 0.19V audio frequency signal is input. The audio band flatness is measured by an audio millivoltmeter. The reference frequency is 1kHz.
Under the conditions of 1kHz, 0.775V input and no input signal, read the values on the audio millivoltmeter respectively. The ratio of the two is the audio signal-to-noise ratio, expressed in decibels.
6.2.12 Audio distortion
6.2.12.1 Measurement block diagram
As shown in Figure 9.
Audio output
Converter under test
Audio signal generator
6.2.12.2 Measurement
Standard modulator
RF output
Standard demodulator
Figure 9 Connection of audio distortion measurement equipment
Distortion meter
Use the standard modulator to modulate the audio signal to the specified channel. The converter under test works on the specified channel with an input level of 75dBμV. The audio signal generator generates a sine wave with a frequency of 1kHz. When switch S is connected to the standard demodulator, adjust the output amplitude of the audio signal generator so that the frequency deviation reading of the standard demodulator is ±50kHz, and use a distortion meter to measure the distortion between RF input and RF output; when switch S is connected to the audio output terminal of the converter under test, use a distortion meter to measure the distortion between RF input and audio output. 6.3 Environmental adaptability
The environmental adaptability test method of the converter shall be carried out in accordance with the relevant provisions of 4.3 of GB/T11318.1-1996. The test temperature group is Group I.
6.4 Reliability
The reliability test method of the converter shall be carried out in accordance with the relevant provisions of 4.4 of GB/T11318.1-1996, and the test plan is Plan 1. 411
6.5 Safety
GB/T11318.13--1996
The safety test method of the converter shall be carried out in accordance with the relevant provisions of 4.5 of GB/T11318.1-1996. 6.6 Electromagnetic compatibility
The electromagnetic compatibility test method of the converter shall be carried out in accordance with the relevant provisions of 4.6 of GB/T11318.1--1996. 7 Inspection rules
7.1 The inspection rules of the converter shall comply with the relevant provisions of Chapter 5 of GB/T11318.1-1996. 7.2 The performance parameter inspection items for acceptance inspection are shown in Table 3.
Sample type
Test items
In-band fluctuation
Adjacent channel carrier suppression
Frequency accuracy
Video signal modulation
Image carrier output level
Image-sound carrier frequency spacing
Note: "0" indicates the item to be tested, "—" indicates no such item. 8 Marking, packaging, transportation and storagebZxz.net
The marking, packaging, transportation and storage of the converter shall comply with the relevant provisions of Chapter 6 of GB/T11318.1-1996. 112
See Table A1 for the TV channel frequency configuration.
Channel code
GB/T11318.13—1996
Appendix A
(Standard Appendix)
TV channel frequency configuration
Frequency range
48.5~56.5
56.5~~64.5
64.5~72.5
76.0~84.0
84.0~92.0
111.0~119.0
119.0127.0
127.0-~135.0
135.0~143.0
143. 0~~151. 0
151. 0~159.0
159.0~167.0
167.0~175.0
175.0~183. 0
183.0~191.0
191.0~~199.0
199.0~207.0
207.0~~215. 0
215.0~~223. 0
223. Q~~231. 0
231.0~239.0
239.0~247.0
247.0~~255. 0
255. 0~~263.0
263.0~271.0
271.0~~279. 0
279.0~287. 0
287.0~295.0
295. 0~303. 0
303.0~~311.0
311.0~~319. 0
319.0~327.0
327.0~335. 0
335.0~343.0
343.0~351.0
351.0359.0
359.0~367.0
367.0~375. 0
375.0~383.0
383. 0~~391. 0
TV channel frequency configuration
Image carrier frequency
Sound carrier frequency
Channel code
GB/T 11318. 13-—1996
Table A1 (end)
Frequency range
391.0~399.0
399.0~~407.0
407.0~~415.0
415.0~-423.0
423.0~~431.0
431.0 ~439.0
439.0~447.0
447.0~455.0
455.0~463.0
470.0~478.0
478. 0~486.0
486.0~494.0
494.0~502.0
502.0~510.0
510.0~518.0
518.0~526.0
526.0~534.0
534.0-~542.0
542.0~550.0
Image carrier frequency
Audio carrier frequency
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