1、SMPTE STANDARD SMPTE 344M-2000 for Television - 540 Mb/s Serial Digital Interface 1 Scope This standard specifies a serial digital interface that operates at a nominal rate of 540 MWs. This standard has application in the television studio over lengths of coaxial cable where the signal loss does not
2、 exceed an amount specified by the receiver manufacturer. Typical loss amounts would be in the range of 20 dB to 30 dB at one-hat the clock frequency with appro- priate receiver equalization. Receivers designed to work with lesser signal attenuation are acceptable. Separate SMPTE documents specify t
3、he mapping of source image formats onto the specified 540 Mb/s serial interface. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standar
4、ds are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below: SMPTE 291 M-1998, Television - Ancillary Data Packet and Space Formatting Page 1 of 5 pages SMPTE RP 184-1
5、996, Specification of Jitter in Bit- Serial Digital Systems IEC 60169-8 (1978-01), Radio Frequency Connec- tors, Part 8: R.F. Coaxial Connectors with Inner Di- ameter of Outer Conductor 6.5 mm (0.256 in) with Bayonet Lock - Characteristic Impedance 50 Ohms (Type BNC) 3 Signal levels and specificatio
6、ns The specifications in this clause are defined for meas- urement of the serial output of a source derivedfrom a parallel domain signal whose timing and other characteristics meet good studio practices. Specifi- cations at the output of equipment located at other places in an all-serial digital cha
7、in are not ad- dressed by this standard. Clock frequency is the serial clock and is equal to 540 MHz. 3.1 The output of the generator shall be meas- ured across a 75-ohm resistive load connected through a short coaxial cable. Figure 1 depicts the measurement dimensions for amplitude, rise- time, and
8、 overshoot (see annex A for the pre- ferred measurement method for these parameters). Overshoot 1 Amplitude Riseti me I Figure 1 - Waveform measurement dimensions CopyrighlQXXX) by THECOCIEPIOF MOTION PICTURE AND TELRIISION ENGINEERS 595 W. Hartsdale Ave white Plains. NY 10507 (914) 761-1100 Approve
9、d September 27,2000 STDOSMPTE 344M-ENGL 2000 8357401 0004247 T34 SMPTE 344M-2000 3.1.1 The generator shall have an unbalanced output circuit with a source impedance of 75 ohms and a return loss of at least 15 dB over a frequency range of 5 MHz to 540 MHz. 3.1.2 The peak-to-peak signal amplitude shal
10、l be 800 mV f 10%. are defined in SMPTE RP 184 and shall have the values in table 1 for compliance with this standard. 3.6 The input to the serial receiver signal shall present an impedance of 75 ohms with a return loss of at least 15 dB over a frequency range of 5 MHz to 540 MHz. 3.2 The dc offset,
11、 as defined by the mid-ampli- tude point of the signal, shall be nominally 0.0 V i 0.5 V. 3.3 The rise and fall times, determined between the 20% and 80% amplitude points, shall be no less than 0.40 ns, no greater than 0.80 ns, and shall not differ by more than 0.2 ns. 3.4 Overshoot of the rising an
12、d falling edges of the waveform shall not exceed 10% of the amplitude. 3.5 The jitter in the timing of the transitions of the data signal shall be measured in accordance with SMPTE RP 184. Measurement parameters 4 Connector and cable types 4.1 The connector shall have mechanical char- acteristics co
13、nforming to the 50-ohm BNC type. Mechanical dimensions of the connector may produce either a nominal 50-ohm or nominal 75-ohm impedance and shall be usable at frequencies up to 540 MHz based on a return loss that is greater than 15 dB. However, the electrical characteristics of the connector and its
14、 associated interface circuitry shall provide a resistive impedance of 75 ohms. Where a 75-ohm connector is used, its mechanical characteristics must reliably interface with the nominal 50-0hm BNC type defined by IEC 60169-8. Table 1 - Measurement parameters Timing jitter lower band edge 10 Hz fl Al
15、ignment jitter lower band edge 1 kHt f2 Upper band edge 1/10 clock rate f3 Timing jitter (note I) 0.2 UI p-p Al Alignment jitter, UI = unit interval 0.2 UI p-p A2 Test signal (note 2) Serial clock divider (note 3) f 10 N Color bars NOTES 1 Designers are cautioned that the clock in parallel signals c
16、onforming to interconnection standards may contain large amounts of jitter. Deriving the serial signal directly from the unfiltered parallel clock could result in excessive serial signal jitter (see annex B for more information on timing jitter). 2 Color bars are chosen as a nonstressing test signal
17、 for jitter measurements. Use of a stressing signal with long runs of zeros may give misleading results. 3 Use of a serial clock divider value of 1 O is acceptable; however, it may mask word-correlated jitter components. The divider value should be stated in conjunction with jitter specifications. P
18、age 2 of 5 pages U STD-SMPTE 344M-ENGL 2000 W 8357403 0004248 970 SMPTE 344M-2000 4.2 Application of this standard does not require a particular type of coax. It is necessary for the coax to be a 75-ohm coax and for the frequency response of the coax, in decibels, to be approxi- mately proportional
19、to 1/ SQRT (f) from 1 MHz to 540 MHz to ensure correct operation of auto- matic cable equalizers over moderate to rnaxi- mum lengths. 4.3 Return loss of the correctly terminated trans- mission line shall be greater than 15 dB over a frequency range of 5 MHz to 540 MHz. when encoding signals. The ord
20、er of Gi(X) and G2(X) is reversed when decoding signals. The input signal to Gi(X) shall be positive logic (the highest voltage represents data 1 and the lowest voltage data O see annex CI). 5.3 The data word length shall be 10 bits. 6 Transmission order The LSB of any data word shall be transmitted
21、 first. 7 Serial data format 5 Channel coding 5.1 The channel coding shall be scrambled NRZI. 5.2 The generator pol nomial for the scrambled NRZ shall be Gl(X) = X + X4 + 1. The polarity-free scrambled NRZI sequence shall be produced by G2(X) = X + 1. GI (X) shall be applied before G2(X) !l 7.1 To m
22、aintain synchronization and word align- ment at the serial receiver, EAV and SAV timing references shall be inserted into the data stream. 7.2 EAV and SAV timing references shall be inserted on a line basis and shall be formatted as shown in figures 2 and 3. Figure 2 - Television horizontal line dat
23、a EAV SAV Figure 3 - Timing reference format Page 3 of 5 pages STD-SMPTE 344M-ENGL 2000 8357401 0004247 807 = SMPTE 3441111-2000 7.3 The maximum spacing between SAV and EAV timing references shall be 60 ps. in the relevant source format mapping docu- ment. 7.4 Available ancillary data space is defin
24、ed by the source format. The ancillary data header shall consist of the three words OOOh, 3FFh, 3FFh with formatting of the ancillary data packet defined by SMPTE 291M. Data values OOOh to 003h and 3Fch to 3FFh are excluded from user ancillary data. 7.5 Data words 3FF and 000 shall be used only for
25、EAV/SAV timing references and ancillary data headers. Source format mapping documents shall ensure that 3FF and O00 are treated as reserved words. Source format mapping docu- ments shall ensure compatibility with 8-bit systems by ensuring that data values in the range 3FCh to 3FFh are treated as equ
26、ivalent to 3FFh for the purpose of detecting ancillary data flags or EAV/SAV timing references. 7.6 Appropriate values for XYZ words within EAV and SAV timing references shall be defined 7.7 Since not all source formats have the same timing reference data, a modification may be required prior to ser
27、ialization in order to meet the requirements of 7.1 and 7.2. Where additional words are required for EAV/SAV sequences, data words from the adjacent digital blanking area shall be used. Modifications are typically made using a coprocessor in the parallel do- main. Source format mapping documents sha
28、ll define the details of such modifications. 8 Source format mapping documents Source format mapping documents shall specify the mapping of source image formats onto the 540 Mb/s serial interface defined in this stand- ard. Mapping documents shall specify how to generate 54 MHz parallel data streams
29、 appropri- ate for serialization in accordance with this standard. Annex A (informative) Waveform measurement method The preferred method for measuring serial digital waveform amplitude, risetime, and overshoot is using an oscilloscope with at least a 2-GHz bandwidth. Input impedance of the oscillos
30、cope should be 75 ohms with a return loss greater than 20 dB to 540 MHz. Measurements should be made using a 2-m length of high-quality coax between the trans- mitter and the oscilloscope. Annex B (informative) Timing jitter specification Low-frequency jitter in the range of 10 Hz to 1 kHz is indica
31、ted by the difference between timing jitter (Al) and alignment jitter (A2) measurements. Although purely digital systems will operate correctly with significant amounts of low-frequency jitter, this standard (3.5) specifies a tight tolerance for timing jitter to ensure operation in mixed digitallana
32、log systems. Page 4 of 5 pages Annex C (informative) Generator polynomial implementations Daia In Generator polynomial implementations are shown in figures C.1 and C.2. D+D+D+D+D+D+D+D+D - Gi(X) = X9 + X4+ i G20() = x + i (NU) Figure C.l - Possible generator polynomial - Method 1 t - U Gq(X)=X9+X4+l
33、 G2(X)=X+ 1 Descrambier U I Figure C.2 - Possible generator polynomial - Method 2 Annex D (informative) Bibliography ANSUSMPTE 259M-1997, Television - 10-Bit 4:2:2 Component and 4f Composite Digital Signals - Serial Digital In te rface SMPTE 292M-1998, Television - Bit-Serial Digital Inter- face for High-Definition Television Systems Page 5 of 5 pages
