1、 ANSI/CEA Standard DTV Remodulator Specification ANSI/CEA-762-B R-2015 February 2015 NOTICE Consumer Electronics Association (CEA) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchaser
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8、A R4.8 DTV Interface Subcommittee.) Published by CONSUMER ELECTRONICS ASSOCIATION 2015 Technology Phone 800-854-7179; Fax 303-397-2740; Internet http:/; Email ATSC Standards: Advanced Television Systems Committee (ATSC), 1750 K Street N.W., Suite 1200, Washington, DC 20006; Phone 202-828-3130; Fax
9、202-828-3131; Internet http:/www.atsc.org/standards.html IEC Standards: Global Engineering Documents, World Headquarters, 15 Inverness Way East, Englewood, CO USA 80112-5776; Phone 800-854-7179; Fax 303-397-2740; Internet http:/; Email IEC Central Office, 3, rue de Varembe, PO Box 131, CH-1211 Gene
10、va 20, Switzerland; Phone +41 22 919 02 11; Fax +41 22 919 03 00; Internet http:/www.iec.ch; Email pubinforiec.ch CEA-762-B R-2015 2.3 Informative References The following standards contain provisions that, through reference in this text, constitute informative provisions of this standard. At the ti
11、me of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed in 2.4. 2.4 Informative Reference List CEA-CEB5-B,
12、Recommended Practice for DTV Receiver “Monitor” Mode Capability (May1, 2007). A/54A Guide to the Use of the ATSC Digital Television Standard, with Corrigendum No. 1 (4 December 2003, Corrigendum No. 1 dated 20 December 2006) 2.5 Informative Reference Acquisition ANSI/CEA Standards: Global Engineerin
13、g Documents, World Headquarters, 15 Inverness Way East, Englewood, CO USA 80112-5776; Phone 800-854-7179; Fax 303-397-2740; Internet http:/; Email ATSC Standards: Advanced Television Systems Committee (ATSC), 1750 K Street N.W., Suite 1200, Washington, DC 20006; Phone 202-828-3130; Fax 202-828-3131
14、; Internet http:/www.atsc.org/standards.html 3 DTV Remodulator RF Output Specifications The entire transport modulation system shall be compliant with ATSC Document A/53B, Annex D, Section 4. 3.1 Selectable Output Channel Frequency The preferred selectable output channel frequency shall be Channel 3
15、 or Channel 4. The nominal channel frequency tolerance shall be within + or 10 KHZ of the desired band. If the selectable output channel frequency is any other group of two VHF or UHF RF channels, they shall be selected from CEA-542-B channels 2 through 51 (inclusive). All devices equipped with RF m
16、odulators shall be clearly marked indicating the available output channels. Note: Channels 3 and 4 are RF frequency channels referenced from CEA-542-B. 3.2 Nominal RMS Output Level The Nominal RMS Output level shall be -3 dBmV (+6/-3 dB) at 75 ohms. Note: Nominal output signal is based on a reductio
17、n of 3 to 6 dB from typical NTSC levels. The value of 3dBmV at 75 ohms is equivalent to 51.8 dBm in the entire VSB signal (which includes 0.3 dB for the pilot), or 119.4 dBm/Hz in the data portion of the spectrum. 3.3 Pilot Phase Noise Pilot Phase Noise shall be less than -90 dBc at 20 kHz. Note: Th
18、e specification is 12 dB better than the demonstrated threshold of 78 dBc at 20 kHz for 8 VSB reception. 3 CEA-762-B R-2015 3.4 Modulation Error Ratio (MER) The MER, without equalization, shall be at least 18 dB below the measured output power. Note: The value is set to allow simple filtering withou
19、t phase correction in the remodulator, while leaving sufficient tolerance for additional linear distortion due to home wiring. The MER, with bandpass equalization, shall be at least 24 dB below the measured output power. Note: The value effectively sets a limit on non-linear distortions in the remod
20、ulator. 3.5 Output Impedance The output impedance shall be 75ohms +/-10%. 3.6 Connector The connector shall be an F-type female connector per IEC 60169-24 (1991-11). 3.7 Side-band Output A double side-band output is acceptable. All spurious signals that are greater than 12 MHz from the pilot of the
21、desired channels output signal shall be more than 30 dB down from the average transmitted power. See Figure 1. CEA-762-B R-2015 PilotBandEdge+6 MHz-6 MHz+12 MHz-12 MHzTransmittedChannel6 MHz BWUnusedLowerSide-band-30 dBChannel Filter Bandwidth = +/- 12 MHzfrom transmitted pilotAttenuation +/- 12 MHz
22、 = -30 dBfrom average transmitted powerFigure 1 Roll-Off Illustration 3.9.1 Spectrum Analyzer Settings Span: 30MHz Frequency set to pilot Resolution BW: 10KHz Video BW: 1KHz 4 DTV RF Remodulator Recommended Input 4.1 Input Overview An overview of input to the DTV remodulator is provided in Figure 2.
23、 In general: a) The remodulator shall support an 8 VSB modulation scheme with an 8 VSB transport stream. Note: support for 16 VSB modulation of ATSC is optional. b) The f(sym) is equal to 10,762,238Hz. (4.5E6 x 648/286) +/- 10 ppm. c) Data and clock rates should be as indicated in Table 1. 5 CEA-762
24、-B R-2015 Figure 2 Re-Modulator System 4.2 Input Recommendations from Remodulator to Source In general, it is recommended that: a) The IRC (Interface Reference Clock) is generated from the Master Clock to provide the frequency reference b) The Data_Request is generated to provide timing for the data
25、 pull from the source device. (Active High for 188 cycles) c) The first byte of packet which is 0x47 or MPEG Sync has been removed in Buffer. d) There are 313 packet cycles, 312 with Data_Request active and 1 with Data_Request inactive. 4.3 Input Recommendations from Source to Remodulator In general
26、, it is recommended that: a) The In_Data is an 8 bit Parallel (Byte Wide) data bus. b) The Data_Valid is active high (for 188 cycles) starting at packet sync (0x47). See Figure 3. c) There are 313 packet cycles, 312 with Data_Valid active and 1 with Data_Valid inactive. Baseband Data Source (or) Inp
27、ut Buffer ATSC MPEG-2 DATA Packets Re-Modulator In_Data70 Data_Valid Data Request Interface Reference Clock (IRC) Master Clock CEA-762-B R-2015 Figure 3 Data_Valid Timing VSB Mode IRC (Interface Reference Clock) Input Data Rate bits/sec Input Data Rate Bytes/sec 16 VSB15,381,118 38,785,317 4,848,164
28、 8 VSB 2,690,559 19,392,658 2,424,082 Table 1 Data and Clock Rates 5 Measurement Measurement of the values specified herein shall be with respect to an impedance of 75 ohms +/- 1%. This tolerance has no other applicability. 1See Section 4.1. item a 47H D0 D1 D186D185D184Byte_ClkIn_Data70Data_ValidHi
29、gh for 188 CyclesIRCData_RequestHigh for 188 Cycles3 1/2 cycle Delay7 CEA Document Improvement Proposal If in the review or use of this document a potential change is made evident for safety, health or technical reasons, please email your reason/rationale for the recommended change to standardsce.org. Consumer Electronics Association Technology & Standards Department 1919 S Eads Street, Arlington, VA 22202 FAX: (703) 907-7693 standardsce.org
