Serial digital interface system transmission/reception...

Television – Format – Including additional information

Reexamination Certificate

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Details

C348S473000, C348S426100

Reexamination Certificate

active

06618095

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a method of transmitting and receiving signals by a serial-digital-interface system employed in a broadcasting studio, and a transmitter and a receiver in the same system.
BACKGROUND ART
Various types of serial-digital-interface systems (hereinafter referred to as SDI system) are employed in studios of a broadcasting station. The SDI systems serialize digital video signals in various formats, then transmit the signals between video-editing devices used in the studios, thus the SDI systems must be compatible with respective formats of video signals. The Society of Motion Picture and Television Engineers (SMPTE) and The Association of Radio-wave Industrial Business (ARIB) standardized SMPTE259M standard, SMPTE292M standard, and BTA S-004B standard and so on. Those standards specify formats of serializing digital-video-signals of various formats in parallel form. The “SCOPES OF SMPTE STANDARD” describes that SMPTE259M standard specifies an SDI of 10-bit (4:2:2) component signal operating at 270 Mbps, and SMPTE292M standard specifies an SDI operating at approx. 1.5 Gbps for component signals of High-Definition-Television (HDTV).
Those standards tell that numbers of source formats differing in the following items are used in broadcasting stations: frame frequency, a number of active scanning lines, a number of pixels per frame, scanning method (interlace, progressive methods). For instance, the video signals in such various formats follows are available in the studios:
Standard Definition Television (SDTV) signal:
scanning-lines; 525
frame frequency: 30/1.001 Hz
scanning method: interlace 480/60 I (hereinafter referred to as 480/60 I)
SDTV signal:
scanning-lines; 525
active lines: 487
frame frequency: 60/1.001 Hz
scanning method: progressive 480/60 P (480/60 P)
HDTV signal:
scanning-lines; 1125
active lines: 1080
frame frequency: (30/M) Hz
scanning method: interlace 1080/60 I
HDTV signal:
scanning-lines; 1125
active lines: 1035
frame frequency: (30/M) Hz
scanning method: interlace 1035/60 I
HDTV signal:
scanning-lines; 750
active lines: 720
frame frequency: (60/M) Hz
scanning method: progressive 720/60 P
where M represents 1 or 1.001.
When one of the STDV video signals, i.e. a signal of 480/60 I method, is serialized and transmitted in accordance with the SMPTE259M standard which is one of SDIs for the SDTV, the signal undergoes the following processes.
FIG. 2
illustrates a sampling structure per frame of the video signal by 480/60 I system. The format of this video signal is as follows: frame frequency=30/1.001 Hz, a number of scanning lines=525, a number of samples (words) per scanning line =858, a number of active samples (words)=720, a sampling frequency=13.5 MHz. This luminance signal and two color-difference signals are sampled at one half the frequency of luminance signal, and then multiplexed to form a multiplexed color signal. This multiplexed color signal, is multiplexed to the luminance signal in each word, then transmitted at 270 Mbps.
On the other hand, when one of HDTV signals, i.e. a video signal of 1080/60 I method, is serialized and then transmitted in accordance with the SMPTE292M standard, or BTA S-004 standard which is one of SDIs for the HDTV, the signal undergoes the following processes. The format of this video signal is as follows: frame frequency=30/1.001 Hz, a number of scanning lines=1125 (1080 active), a number of samples (words) per scanning line=2200, a number of active samples (words)=1920, a sampling frequency=74.25/1.001 MHz. The luminance signal and color-difference signals are structured in the same way as discussed above. The luminance signal and color difference signals are multiplexed to each word, then transmitted at 1.485/1.001 Gbps.
FIG. 25
illustrates a structure of a conventional SDI system compatible both with the HDTV and SDTV. This SDI system comprises transmitter
309
and receiver
315
. In transmitter
309
, parallel-video-data (video signal (1) in
FIG. 25
) in HDTV, 1080/60 I format and another parallel-video-data (video signal (2) in
FIG. 25
) in SDTV, ‘480/60 I’ format comprises luminance signals (hereinafter referred to as Y-signal) in 10-bit, and multiplexed color-difference signals (hereinafter referred to as C-signal). This parallel-video-data are fed into HD interface formatting circuit
306
and SD interface formatting circuit
326
respectively in 20-bit parallel form. In these formatting circuits
306
and
326
, an end of active video (EAV) signal as well as a start of active video (SAV) signal is multiplexed to respective Y and C signals. The EAV signal is a timing-reference signal indicating an end of horizontal and vertical active periods, while the SAV signal is a timing-reference signal indicating a start thereof. Line number data and an error-detecting-code are also multiplexed to Y and C signals in formatting circuit
306
, and they are supplied as an interface format. Output from interface formatting circuits
306
and
326
are fed into parallel to serial converting circuits (hereinafter referred to as a P/S converting circuit)
307
and
327
, where the least significant bit (LSB) of C-signal and onward including C-signal and Y-signal in this order undergo the P/S conversion and then they are output to scrambling circuits
308
and
328
. Circuits
308
and
328
scramble the input signals with generating function (X
9
+X
4
+1) (X+1), and output them. The signals scrambled in circuit
308
are converted into voltages in accordance with the SMPTE292M standard by a voltage-converting-circuit (not shown), and are output as a serial signal. A transmitting speed of the HDTV signal output here is approx. 1.5 Gbps. The signal scrambled in circuit
328
is converted into a voltage in accordance with the SMPTE259M standard, and output as a serial signal. A transmitting speed of the SDTV signal output here is approx. 270 Mbps.
Those signals are fed into receiver
315
, where waveform-equalizing circuits
310
and
330
receive the serial signals of HDTV and SDTV from transmitter
309
. Circuits
310
and
330
compensate degraded signals due to a coaxial cable used in the transmission line, and equalize the waveforms thereof then output the signals. Clock reproducing circuits
311
and
331
receive the output from waveform-equalizing-circuits
310
and
330
, extract clock component thereby reproducing a clock signal, then output serial data and serial clock signal. De-scrambling circuits
312
and
332
receive the serial data as well as the serial clock signal from circuits
311
and
331
, and then descramble and output them. Serial to parallel converting circuits (S/P converting circuit)
313
and
333
receive the serial data descrambled, and convert the data into parallel form, then output the parallel data. HD interface deformatting circuit
314
and SD interface deformatting circuit
334
receive the parallel data from circuits
313
and
333
, and convert them into video-parallel-data in the same format as the signals have been fed into transmitter
309
, then output the data. As discussed above, respective SDI systems for SDTV and HDTV are prepared independently, and thus each type of signals employs respective appropriate systems.
If various video formats, e.g. HDTV and SDTV, can be transmitted through an identical SDI system and an identical transmission line, and further if the SDI system can transmit a plurality of channels, it will produce great advantages in this industry. The advantages include, (a) reducing a number of transmission lines, (b) simplifying the work of preparing the transmission lines, (c) downsizing the circuit of SDI system, and (d) reducing the cost of SDI system. However, when the various formats discussed above are serialized, transmission speed thereof may be 270 Mbps for SDTV, 480/60 I format, and 540 Mbps for SDTV, 480/60 P format (for instance, 270 Mbps through two lines). On the other hand, serialized HDTV format produce the transmission spee

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