Transcript
Attachment 1 1.
Reference test methods for examination of cable broadcasting and television systems Test method for electric wave leakage:
(1) Instruments required: 1. Half-wave dipole antenna, calibrated; 2. Band-pass filter; 3. Pre-amplifier; and 4. Wave leakage tester. (2) Test procedure: 1. Test 3/4 or more of the total length of aerial lines above feed lines (included) in the entire area and document the locations where the upper limit of maximum wave leakage is exceeded, amount of wave leakage, wave leak age frequency and measurement distance. 2. The test result shall not exceed the upper limit of wave leakage specified in the Specifications. Exceeding the upper limit is considered failing to meet the Specifications. 3. For frequency bands within the range from 225 to 400 MHz, the accumulated wave leakage index exceeding 64 is failure to meet the Specifications, and will be reported to the competent authority immediately. 1
n
Accumulated wave leakage index 2 =10·log
(－
Ei 2
)
i=1 ｎ: Number of locations where the eave leakage is greater than or equal to 50μV/m. Ei : Wave leakage measured greater than or equal to 50μV/m at the measurement distance of 3m. : Fraction of length of cable accutally used for wave leakage measurement equal to length of wave leakage cable divided by the length of cable in the entire area (no less than 0.75)
(3) Test steps: 1. See Figure 1 for test setup.
2. Adjust the length of dipole antenna to half of the wavelength to be tested multiplied by 0.95; or adjust the antenna length according to the frequency length chart provided by the antenna manufacturer for the antenna used, if any. 3. Place the antenna 3m from the coaxial cable to be tested and more than 3m from the ground or other conductive body. 4. Rotate the antenna on the horizontal plan and document the maximum wave leakage. The wave leakage is calculated as: E=V+D+L-G Ｅ: wave leakage (dBμV/m) Ｖ: spectrum analyzer reading (dBμV) Ｄ: dipole antenna factor (dB/m) Ｌ: loss from antenna to spectrum analyzer (dB) Ｇ: pre-amplifier gain (dB) In case that the dipole antenna factor is not provided, it can be determined as: D=20log(f)-33.7 Where ｆ is the test frequency in MHz. 5. For wave leakage test on a frequency lower than 54MHz or higher than 216MHz, if the measurement at 3m is greater than 67μV/m, move the antenna to 10m from the coaxial cable, repeat Step 4 and document the maximum wave leakage. 2. Test method for carrier level: (1) Instruments required: 1. Adjustable band-pass filter or band-pass filter for the channel to be tested (with noise bandwidth of at least 6 MHz). 2. Variable attenuator. 3. Spectrum analyzer (with resolution bandwidth of 300kHz) (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition,
for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at the very end of the distribution network. 3. Measurement shall be taken at every subscriber terminal (or tap) selected for the testing. The system fails to meet the Specifications if any of the test points selected fails to meet the criteria set for the Specifications. (3) Test steps: 1. See Figure 2 for test setup. 2. Tests shall be done using a spectrum analyzer. 3. Test method for carrier to noise ratio: (1) Instruments required: 1 Adjustable band-pass filter or band-pass filter for the channel to be tested (with noise bandwidth of at least 6 MHz). 2. Variable attenuator 3. Pre-amplifier (gain: 20 to 30dB, noise index < 10dB) 4. Spectrum analyzer (with resolution bandwidth of 300kHz) 5. Thermometer (capable of measuring from -20°C to +60°C) (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and
up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at the very end of the distribution network. 3. 5 channels shall be selected for each examination point for systems with bandwidth smaller than 750MHz. For bandwidth greater than 750MHz, one additional channel shall be selected for every additional 100MHz. The bandwidth less than 100MHz is considered 100MHz. The channels selected for testing shall be distributed evenly across low, medium and high bands. The system’s carrier to noise ratio fails to meet the Specifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test steps: 1. See Figure 2 for test setup. 2. Document the temperature at the time of testing. 3. Adjust the spectrum analyzer as follows: Resolution bandwidth: 300kHz Video bandwidth: 100Hz (do not exceed 300Hz) Vertical scale: 10 dB/grid Horizontal scale: 1 MHz/grid Scan time: set at automatic 4. Without any input, adjust the input attenuation of the spectrum analyzer so that the lower limit of noise ratio is 70dB or more lower than the top of the scale. 5. Adjust the analyzer to the video carrier frequency of the channel to be tested. 6. In case that the channel to be tested is modulated, adjust the analyzer as follows: Resolution bandwidth: 1MHz or 3MHz Video bandwidth: 10kHz Vertical scale: 2dB/grid Spread spectrum rage: 10kHz Scan time: set at automatic 7. Adjust the band-pass filter and fine-tune the analyzer to
capture the maximum reading other video carrier. 8. Adjust the variable attenuator so that the peak of video carrier falls on the topmost scale line of the analyzer. This line is the reference line for the test. 9. Re-adjust the analyzer as in Step 3. 10. Adjust the analyzer so that the video carrier peak is located at the center of display. 11. Turn off the channel to be tested or at least remove the modulation signal (for the purpose of this test, do not select the carrier used for automatic gain control or automatic slope control). 12. At where the frequency is greater than the video carrier frequency, select a point of which the energy is the minimum on the analyzer. This point is usually located approximately 2-3MHz to the right hand side of video carrier. Adjust the center frequency of the variable bandpass filter to this point and document the dB difference between this point and the topmost scale line. 4. Test method for carrier composite beat ratio: (1) Instruments required: 1. Variable attenuator 2. Adjustable band-pass filter or band-pass filter for the channel to be tested (with noise bandwidth of 1 to 6 MHz). 3. Spectrum analyzer (with resolution bandwidth of 30kHz and video bandwidth of 10Hz) (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the
video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at the very end of the distribution network. 3. 5 channels shall be selected for each examination point for systems with bandwidth smaller than 750MHz. For bandwidth greater than 750MHz, one additional channel shall be selected for every additional 100MHz. The bandwidth less than 100MHz is considered 100MHz. The channels selected for testing shall be distributed evenly across low, medium and high bands. The system’s carrier composite beat ratio fails to meet the Specifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test steps: 1. See Figure 2 for test setup. 2. Adjust the spectrum analyzer as follows: Resolution bandwidth: 30kHz Video bandwidth: 10Hz Vertical scale: 10 dB/grid Horizontal scale: 50kHz/grid Scan time: 0.2 sec/grid 3. Adjust the center frequency of the spectrum analyzer to video carrier frequency to be tested. 4. Adjust the input attenuation and reference level of the analyzer so that the carrier peak falls on the topmost scale line on the analyzer. This line is the reference line for the test. 5. Turn off the carrier to be tested. What is shown on the analyzer at this moment is the composite triple beat (CTB) and its difference from the reference level is the composite third order (CTO). 6. Adjust the center frequency of the analyzer to video carrier frequency to be tested plus 0.75MHz. 7. What is shown on the analyzer at this moment is the composite double beat (CDB) and its difference from the reference level is the composite second order (CSO). 8. Adjust the center frequency of the analyzer to video
carrier frequency to be tested plus 1.25MHz. 9. What is shown on the analyzer at this moment is also CDB and its difference from the reference level is CSO. 10. The carrier composite beat ratio is the smallest of measurements from Steps 5, 7 and 9. 5. Test method for cross modulation ratio: (1) Instruments required: 1. Continuous wave generator or multi-channel signal generator (capable of 100% synchronized square-wave modulation at 15734 ±20Hz) 2. Spectrum analyzer 3. Band-pass filter for the channel to be tested or adjustable band-pass filter (with bandwidth of 1 to 6 MHz) (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at the very end of the distribution network. 3. 5 channels shall be selected for each examination point for systems with bandwidth smaller than 750MHz. For bandwidth greater than 750MHz, one additional channel shall be selected for every additional 100MHz. The bandwidth less than 100MHz is considered 100MHz. The channels selected for testing shall be distributed evenly across low, medium and high bands. The system’s cross modulation ratio fails to meet the Specifications if any channel selected for testing at any point fails to meet the
criteria specified for the Specifications. (3) Test steps: 1. See Figure 2 for test setup. 2. Adjust every carrier to the lowest level required by the system. 3. Modulate all carriers with 87.5% square wave except the channel to be tested. 4. Adjust the center frequency of the spectrum analyzer to the video carrier to be tested. 5. Adjust the analyzer to show ±15kHz of sideband. 6. Measure and document the difference in amplitude between 15kHz sideband and center frequency. 7. The cross modulation is calculated by subtracting 10dB from the difference in amplitude. 6. Test method for carrier hum noise modulation ratio: (1) Instruments required: 1. RF signal generator or television modulator capable of generating continuous waves, television converter. 2. RF level meter (with video output) 3. Low-pass filter (1kHz) 4. Spectrum analyzer (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at the very end of the distribution network. 3. 5 channels shall be selected for each examination point for systems with bandwidth smaller than 750MHz. For
bandwidth greater than 750MHz, one additional channel shall be selected for every additional 100MHz. The bandwidth less than 100MHz is considered 100MHz. The channels selected for testing shall be distributed evenly across low, medium and high bands. The system’s carrier hum noise modulation ratio fails to meet the Specifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test steps: 1. See Figure 2 for test setup. 2. Use the RF signal generator to input a continuous wave to be tested at the head end. Its level shall be the same as the system’s video carrier level. 3. Test with the spectrum analyzer. 7. Test method for carrier beat ratio: (1) Instruments required: 1. Variable attenuator 2. Band-pass filter for the channel to be tested (bandwidth from 10 to 14 MHz) 3. Spectrum analyzer (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at the very end of the distribution network. 3. 5 channels shall be selected for each examination point for systems with bandwidth smaller than 750MHz. For
bandwidth greater than 750MHz, one additional channel shall be selected for every additional 100MHz. The bandwidth less than 100MHz is considered 100MHz. The channels selected for testing shall be distributed evenly across low, medium and high bands. The system’s carrier beat ratio fails to meet the Specifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test steps: 1. See Figure 2 for test setup. 2. Adjust the center frequency of the spectrum analyzer to the video carrier frequency to be tested. 3. Adjust the input attenuation and reference level of the analyzer so that the carrier peak-to-peak value falls on the topmost scale line of the analyzer. This line is the reference line. 4. Turn off the carrier to be tested. Adjust the resolution bandwidth and video bandwidth of the analyzer to show the peaks of all signals on screen. 5. Compare the signal values shown against the required value. 8. Test method for subscriber terminal isolation: (1) Instruments required: 1. Signal generator 2. RF level meter (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more
of the test points shall be selected from the subscribers at the very end of the distribution network. 3. All channels of the system shall be tested. The system’s subscriber terminal isolation fails to meet the Specifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test steps: 1. See Figure 3 for test setup. 2. Connect the output of signal generator directly to the RF level meter. 3. Adjust the frequency of the signal generator to the video carrier frequency to be tested. 4. Adjust the output level of the signal generator to 18 dBμV. 5. Connect the output of signal generator and input of RF level meter to each of the test ports to test the subscriber terminal isolation. (The difference between the reading of RF level meter and 18 dBμV is the subscriber terminal isolation.) 9. Test method for distribution network frequency response: (1) Instruments required 1. Sweep frequency generator 2. Spectrum analyzer (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every subcarrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The test points selected shall be representative of the video and audio quality of the entire system. 1/3 or more of the test points shall be selected from the subscribers at
the very end of the distribution network. 3. All channels of the system shall be tested at each of subscriber terminals selected for testing. The system’s distribution network frequency response fails to meet the Specifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test steps: 1. See Figure 4 for test setup. 2. Insert sweep frequency signal at the input of head end. This must cover the entire system band. 3. Adjust the frequency range of spectrum analyzer so that it is the same as the system band. 4. Connect the analyzer to the subscriber terminal and measure the frequency response of the distribution network. 10. Test method for head-end carrier frequency: (1) Instruments required: 1. Variable attenuator 2. Band-pass filter for the channel to be tested (bandwidth 10 to 14 MHz) 3. Spectrum analyzer (2) Test procedure: 8 channels are selected at each test point for the system band width below 150 MHz; for bandwidth above 450 MHz, one ad ditional channel is selected for every additional 100MHz of ba ndwidth (the part less than 100MHz is considered 100MHz); th e channels selected for testing must be evenly distributed acros s low, medium and high bands. The frequency converter and m odulator at the head end of system fail to meet the Specificatio ns if any channel selected for testing at any point fails to meet t he criteria specified for the Specifications. (3) Test steps: 1. See Figure 5 for test setup. 2. Measure the output end of the frequency converter and modulator at the head end using the spectrum analyzer.
11. Test method for head-end television frequency converter: (1) Instruments required: 1. Sweep frequency generator 2. Spectrum analyzer (2) Test procedure: 8 channels are selected at each test point for the system band width below 450 MHz; for bandwidth above 450 MHz, one ad ditional channel is selected for every additional 100MHz of ba ndwidth (the part less than 100MHz is considered 100MHz); th e channels selected for testing must be evenly distributed acros s low, medium and high bands. The head-end television frequency converter fail to meet the Specifications if any chann el selected for testing at any point fails to meet the criteria spec ified for the Specifications. (3) Test steps: 1. See Figure 6 for test setup. 2. Connect the sweep frequency generator to the spectrum analyzer. 3. Set the generator at continuous waves. Adjust its frequency at the center frequency of the channel to be tested. 4. Adjust the signal level of the generator at 25dB lower that the upper output limit of the frequency converter. 5. Confirm that the frequency flatness of the sweep frequency generator is smaller than ±0.2dB in 10MHz bands on both side of the center frequency. 6. Rearrange the test setup as shown in Figure 6. 7. Measure and document the frequency response corresponding to the video carrier frequency plus 0.2MHz. 12. Test method for head-end television modulator frquency response: (1) Instruments required: 1. Sideband analyzer (with 0 to 15 MHz of flatness response) 2. Spectrum analyzer (2) Test procedure:
8 channels are selected at each test point for the system band width below 450 MHz; for bandwidth above 450 MHz, one ad ditional channel is selected for every additional 100MHz of ba ndwidth (the part less than 100MHz is considered 100MHz); th e channels selected for testing must be evenly distributed acros s low, medium and high bands. The head-end television modulator frquency response of the system fails to meet the Sp ecifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications. (3) Test step: 1. See Figure 7 for test setup. 2. Adjust the frequency of the spectrum analyzer at the center frequency of the channel to be tested. 3. Adjust the sideband analyzer to display the frequency response of the modulator to be tested. 4. Measure and document the frequency response corresponding to the video carrier frequency plus 0.2MHz. 13. Test method for head-end television modulator differential gain: (1) Instruments required: 1. Video waveform generator (capable of generating modulated step signals) 2. Attenuator 3. Test demodulator 4. Waveform monitor (with chromaticity signal band-pass filter) (2) Test procedure: 8 channels are selected at each test point for the system band width below 450 MHz; for bandwidth above 450 MHz, one ad ditional channel is selected for every additional 100MHz of ba ndwidth (the part less than 100MHz is considered 100MHz); th e channels selected for testing must be evenly distributed acros s low, medium and high bands. The head-end television modulator differential gain of the system fails to meet the Spec ifications if any channel selected for testing at any point fails to meet the criteria specified for the Specifications.
(3) Test step: 1. See Figure 8 for test setup. 2. Input a 5 or 10-step modulated step signal to the television modulator to be tested. 3. Adjust the modulator to generate 87.5% of modulation depth. 4. The modulator output shall be adjusted and attenuator selected so that the output of test demodulator will not overload. 5. Adjust the output level of test demodulator to 1V peakto-peak. 6. Switch the response mode switch on the waveform monitor to band-pass filtering. What is shown on the screen is the color subcarrier signal with the brilliancy signal removed. 7. Calculate the differential gain with the following formula using the linear IRE scale of the waveform monitor: Differential gain (DG) = (VP-Pmax.─VP-Pmin.)/ VP-Pmax. * 100﹪ 14. Test method for head-end television modulator differential phase: (1) Instruments required: 1. Video waveform generator (capable of generating modulated step signals) 2. Attenuator 3. Test demodulator 4. Oscilloscope (bandwidth at least 5 MHz) (2) Test procedure: 8 channels are selected at each test point for the system band width below 450 MHz; for bandwidth above 450 MHz, one ad ditional channel is selected for every additional 100MHz of ba ndwidth (the part less than 100MHz is considered 100MHz); th e channels selected for testing must be evenly distributed acros s low, medium and high bands. The head-end television modulator differential phase of the system fails to meet the Spe cifications if any channel selected for testing at any point fails t o meet the criteria specified for the Specifications. (3) Test steps:
1. See Figure 9 for test setup. 2. Input a 5 or 10-step modulated step signal to the television modulator to be tested. 3. Adjust the modulator to generate 87.5% of modulation depth. 4. The modulator output shall be adjusted and attenuator selected so that the output of test demodulator will not overload. 5. Adjust the output level of test demodulator to 1V peakto-peak. 6. Adjust the gain of test demodulator so that the vector of maximum amplitude of color subcarrier falls on the inscribed circle of the scale dial. 7. Select the differential phase function of the vector analyzer and use the phase knob to select the vectors of maximum and minimum phases (then set the phase of calibrated phase shifter at zero degree). 8. Adjust the calibrated phase shifter to make the maximum and minimum vectors coincide and read the differential phase value. 15. Test method for grounding resistance: (1) Instrument required: Hook-type grounding resistance meter (2) Test procedure: 1. Measure the grounding resistance at head end. The headend grounding resistance test of the system fails to meet the Specifications if the head-end grounding resistance exceeds 15Ω. 2. Randomly select 10% of the grounding points in the area reported for testing. No more than 30 points should be selected. However, for the areas of no arrival for a reason, one point shall be selected for every optical fiber sub-carrier station reported for testing and up to 6 points should be selected. The grounding resistance test of the test points fails to meet the Specifications if the grounding resistance or grounding method at the test points fails to meet the applicable criteria.
(3) Test steps: Measure with the hook-type grounding resistance meter. 16. Test method for bands prohibited for signal transmission: (1) Instruments rquired: 1. Variable attenuator 2. Adjustable band-pass filter (at least 6MHz bandwidth) 3. Spectrum analyzer (2) Test procedure: 1. At least 6 points shall be taken for examination based on the number of villages/boroughs in the examination area as per ordinary level 1 of AQL 4.0 standard. In addition, for the distribution network for which microwave is used for transmission, one additional examination point shall be taken at the end of that microwave transmission network. One examination point is taken from every optical fiber sub-carrier station for the areas of no arrival for a reason, and up to 6 points can be taken. 2. The bands prohibited for signal transmission shall be measured at each subscriber terminal (or tap) selected for testing. The system’s bands prohibited for signal transmission fails to meet the Specifications if any test point fails to meet the criteria of the Specifications. (3) Test step: 1. See Figure 2 for test setup. 2. Adjust the initial frequency to terminal frequency of the spectrum analyzer as per the following four bands: 74 to 76 MHz 108 to 138 MHz 149.9 to 150.0 MHz 156.525 to 156.8405 MHz 3. Adjust the adjustable band-pass filter to the bands to be tested. 4. Adjust the resolution bandwidth and video bandwidth of the spectrum analyzer. Measure and document all the signal frequencies and levels of the bands mentioned above. 17. Test method for uplink control signal band:
(1) Instruments required: 1. Variable attenuator 2. Adjustable band-pass filter (at least 6MHz bandwidth) 3. Spectrum analyzer (2) Test procedure: Measure the uplink control signal bands at head end. The uplink control signal bands of the system fail to meet the Specifications if the criteria of the Specifications are not met. (3) Test steps: 1. See Figure 10 for test setup. 2. Set the initial frequency of the spectrum analyzer at 5MHz and terminal frequency at 42MHz. 3. Adjust the adjustable band-pass filter to the frequency band to be tested. 4. Adjust the resolution bandwidth and video bandwidth of the spectrum analyzer. Measure and document all the signal frequencies and levels of the bands mentioned above. 18. Test method for fixed-address encoding: (1) Instruments required: 1. Spectrum analyzer 2. 3 television sets 3. 1-to-4 distributor x 1 The system operator is to provide the instruments above. (2) Test procedure: 1. Article 41 of the Cable Radio and Television Act specifies that all encoded channels must be measured. The fixed-address encoding of the system fails to meet the Specifications if any of the channels fails to meet the criteria of the Specifications. 2. Only 9 channels are selected for examination in case that there are more than 9 encoded channels. In principle, the channels selected for examination should be distributed evenly at low, medium and high bands. (3) Test steps: 1. See Figure 11 for test setup.
2. The system operator shall mark the address set in the settop box in advance. 3. The system operator shall enter the address in the headend fixed-address encoding control so that the set-top boxes will operate individually. 4. Observe that the video and audio signals of the encoded television are encoded. 5. Test with the spectrum analyzer if the fixed-address signals are transmitted through a prohibited channel. 19. Test method for signal level: (1) Instrument required: spectrum analyzer (with 300kHz of resolution bandwidth) or digital television DVB-C signal analyzer (2) Test steps: 1. See Figure 4 for test setup. 2. Test with the spectrum analyzer or the digital television DVB-C signal analyzer. 3. When measuring with the spectrum analyzer, set the resolution bandwidth at 300kHz and turn on “noise marker” function to measure the center frequency; the signal level = carrier (dBm/Hz)+10×log [baud rate/Hz]. Or observe the signal level directly when using a digital television DVB-C signal analyzer. 20. Test method for modulation error ratio: (1) Instrument required: digital television DVB-C signal analyzer (2) Test steps: 1. See Figure 14 for test setup. 2. Measure with the digital television DVB-C signal analyzer. 3. Set the center frequency and baud rate of the channel to be measured and observe directly the modulation error ratio. 21. Test method for digital television resolution and number of frames: (1) Instruments required: 1. Streaming signal analyzer
2. A television set 3. A set-top box (2) Test procedure: 1. Program channel selection: the channels selected shall cover standard definition (resolution 720×480i or above) and high resolution (resolution 1280×720p or above). One program channel shall be selected for every resolution. Check and document the resolution and number of frames of the system operator’s channels selected for examination. 2. Connect the streaming signal analyzer. Measure the resolution and frame number of elementary stream (ES) using the streaming signals encoded at head end. 3. Connect the set-top box and television set. Observe whether the video feeds of existing program are played normally without mosaic. 4. In case that it is impossible to transmit high definition or other resolution, it is permitted to select a program channel for setting and then perform the examination of the television program resolution. (3) Test steps: 1. See Figure 15 for test setup. 2. Adjust the streaming analyzer to the center frequency of the channel to be tested. 3. Measure and document the resolution and number of frames of the ES (Elementary stream). 22. Test method for digital television program rating function: (1) Instruments required: 1. Streaming signal analyzer 2. A television set 3. A set-top box (2) Test procedure: 1. Check and document the program channels of the system operator selected for testing, and test the manufacturer and model of each set-top box. 2. Connect the streaming signal analyzer. Check the rating of the program in the parental rating description in the
event information table (EIT) using the streaming signals encoded at head end. 3. Connect the set-top box and television and observe whether the existing television programs are encoded according to their ratings. 4. In case that it is impossible to broadcast programs of all ratings, it is permitted to select a program channel for setting and then perform the examination of the television program rating. (3) Test steps: 1. See Figure 15 for test setup. 2. Adjust the streaming analyzer to the center frequency of the channel to be tested. 3. Measure and document the settings in the Parental Rating Description. 4. Document whether the program contents are encoded according to their ratings.
Attachment 2 Test Setup Examples Dipole antenna
Pre-amplifier
Electric wave leakage test meter
Band-pass filter
Figure 1 Electric wave leakage test setup Modulator Continuous wave generator
Switch Subscriber terminal
75Ω
Subscriber terminal
Variable attenuator
Band-pass filter
Figure 2
Spectrum analyzer
Test setup for carrier level, carrier to noise ratio, carrier composite beat ratio, cross modulation ratio, carrier hum noise modulation ratio, prohibited channel and carrier beat ratio
Spectrum analyzer
75Ω Joint
Joint
75Ω Joint
Subscriber tap
Figure 3 Test setup for subscriber terminal isolation
Subscriber terminal
Spectrum analyzer
Figure 4 Test setup for distribution network frequency response
Head end equipment to be tested
Spectrum analyzer
Figure 5 Head end carrier frequency test setup
Sweep frequency generator
Spectrum analyzer Television frequency converter to be tested
Figure 6 Head end television frequency converter frequency response test setup
Sideband analyzer
Spectrum analyzer
Modulator to be tested
Figure 7 Head end television modulator frequency response test setup
Attenuator Modulated step signal
Modulator to be tested
Video waveform generator Test demodulator
Waveform monitor
Figure 8 Head end television modulator differential gain test setup
Attenuator Modulated step signal
Modulator to be tested
Video waveform generator Test demodulator
Vector analyzer
Figure 9 Head end television modulator differential phase test setup
圖十四 頭端電視調變器頻率響應測試裝置
訂戶終端點
Head end signal combiner 可變衰減器
Spectrum analyzer
Band-pass filter
頻譜分析儀
帶通濾波器
Variable attenuator
Figure 10 Uplink control signal band test setup
Spectrum analyzer
Subscriber tap Machine room equipment
Set-top box
Encoding control
Set-top box
Television set
Set-top box
Television set
Figure 11 Fixed-address encoding test setup
Television set
1-to-3 distributor Subscriber terminal
Digital settop box
Spectrum analyzer
Digital signal bit error rate tester
Television set
Figure 12 Test setup for measurement of digital television bit error rate
Subscriber end
Spectrum analyzer Figure 13 Test setup for measurement of ingress noise
Subscriber terminal
Digital television DVB-C signal analyzer
Figure 14 Test setup for measurement of digital cable television modulation error ratio
Head end RF signal equipment Head end digital equipment
RF signal (DVB-C)
Streaming signal (TS)
Digital set-top box
Television set Streaming signal analyzer
Figure 15 Test setup for measurement of digital television program resolution and number of frames, and program rating function
