wt8043 ETC-unknow, wt8043 Datasheet - Page 13

• Manufacturer Part Number: wt8043
• Description: Synchronous Signal Discriminator For Multi-sync Display Monitor
• Manufacturer: ETC-unknow

Appication Description
General Description
Figure 1-1 and 1-2 is a simplified functional block diagram of the WT8043. It
includes the following functional blocks: sync pulse polarity detector; horizontal
and vertical frequency discriminator, mode selector.
The Sync pulse polarity detector accepts separete H and V sync signals with any
polarities. It determines their polarities and sends the polarity information to the
mode selector for video mode selection. It alos generates -H and -V signals in spite
of their input polarities.
The H and V frequency discriminator determines the frequency range of H and V
sync signals. The mode selector determines which operating video mode it should
be, according to the frequency range and polarity of H and V sync signals. The
operating video modes include the standard IBM VGA (640x350, 640x400,
640x480), super VGA (800x600) and IBM8514/A (Inerlaced, Non-interlaced),
VESA VGA & SVGA mode, VESA new SVGA mode, XGA (1024x768), and
1280x1024 mode, also including NEC 24kHz and 3 VESA New 75Hz timing
modes.
The mode selector also generates output signals that represent the frequency range
of H. sync signal. The H sync signal is divided into 6 frequency ranges (3 ranges
for WT8043N20) according to Fig. 2, WT8043 has preset the discriminating points
between frequency ranges. However, it also offers the flexibility for providing
user-defined discriminating points for non-standard video modes.
The digital noise filter is used for rejecting noise on the incoming horizontal and
vertical synchronous signals. The input section uses two techniques to improve
noise rejec-tion. So the low level noise and the large short duration noise spikes
will be rejected. Horizontal synchronous pulse width under 0.56 s and vertical
synchronous pulse width under 0.56 s will be considered as noise.
Weltrend Semiconductor, Inc.
2F., No. 24, Industry E. 9th Rd.
Science-Based Industrial Park
Hsin-Chu, Taiwan, R.O.C.
Tel: [phone]
Fax: [phone]
WT8043
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