ML6426

7

November, 1999

SMPTE

1920

1080

60I

60Hz

35.3KHz

81MHz

40.5MHz

ML6426-6

274M

1920

1080

30P, 24P

60Hz

70.6KHz

162MHz

81MHz

N/A

SMPTE

1280

720

60P, 30P,

60Hz

47.1KHz

60MHz

30MHz

ML6426-5

24P

ML6426-4

704

60I

60Hz

15.7KHz

13.5MHz

6.75MHz

ML6426-1

704

480

60P, 30P,

60Hz

31KHz

27MHz

13.5MHz

ML6426-2

24P

ML6426-4

640

60I

60Hz

15.7KHz

24.5MHz

12MHz

ML6426-2

640

480

60P, 30P,

60Hz

31KHz

12.27MHz

6MHz

ML6426-1

24P

P=progressive scan, I=interlaced scan, na = not available

Note 1: NTSC display rates, can be fed directly into NTSC encoder (set top box)

Note 2: 60 Hz also includes 59.94Hz

Note 3: custom frequencies ranging ± 3 to 6MHz can be special cut to order

Table 2: Choosing the Correct Reconstruction Filter and Video Amplifier for TV Applications, ML6426 options

TYPICAL APPLICATIONS

RECONSTRUCTION FILTER SELECTION FOR HDTV AND

VGA SIGNAL FILTERING

The filtering requirements for HDTV and VGA standards

vary depending on the resolution of the image to be

displayed, and its refresh rate. The actual refresh rate of

the display is not necessarily the same as the transmission

rate of the frames of images. Some formats use a frame

rate of 30Hz, but the display of those formats cannot be

scanned onto the CRT at 30Hz. Excessive large area

flicker would result. Such kinds of flicker can be seen on

a PAL display with its brightness set high. To avoid this,

the video will need to be stored in a frame buffer. This

buffer already exists in the MPEG decoder of HDTV

systems, so there is no cost penalty. The buffer is read out

at twice the rate as the frame rate for 30Hz systems, thus

getting us a refresh rate of 60Hz. Similar things are done

for the 24Hz frame rate formats to boost them to a 60Hz

refresh rate.

PIXELS

VERTICAL LINES

ASPECT RATIO

PICTURE TRANSMISSION RATE

1920

1080

16:9

60I, 30P, 24P

1280

720

16:9

60P, 30P, 24P

704

480

16:9 and 4:3

60P, 60I, 30P,24P

640

480

4:3

60P, 60I, 30P,24P

P=progressive scan, I=interlaced scan

Table 1: HDTV / Advanced TV Applications: (From Table 10.3 from ATSC document A54)