AD9980KSTZ-80 Analog Devices Inc, AD9980KSTZ-80 Datasheet - Page 17

• Manufacturer Part Number: AD9980KSTZ-80
• Description: IC,Data Acquisition Signal Conditioner,3-CHANNEL,8-BIT,CMOS,QFP,80PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD9980KSTZ-80

• Applications: Video
• Interface: Analog
• Voltage - Supply: 3.13 V ~ 3.47 V
• Package / Case: 80-LQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AD9980/PCBZ - KIT EVALUATION AD9980
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Vsync Filter and Odd/Even Fields
The Vsync filter is used to eliminate spurious Vsyncs, maintain
a stable timing relationship between the Vsync and Hsync
output signals, and generate the odd/even field output.
The filter works by examining the placement of Vsync with
respect to Hsync, and if necessary, slightly shifting it in time.
The goal is to keep the Vsync and Hsync leading edges from
switching at the same time, eliminating confusion as to when
the first line of a frame occurs. Enable the Vsync filter with
Register 0x14, Bit 2. Use of the Vsync filter is recom-mended for
all cases, including interlaced video, and is required when using
the Hsync per Vsync counter. Figure 12 illustrates even/odd
field determination in two situations.
HSYNCOUT
HSYNCIN
WINDOW
FILTER
VSYNC
Figure 10. Sync Processing Filter
Rev. 0 | Page 17 of 44
WINDOW
FILTER
QUADRANT
VSYNCOUT
O/E FIELD
HSYNCIN
VSYNCIN
EXPECTED
EDGE
2
FIELD 1
SYNC SEPARATOR THRESHOLD
EQUALIZATION
3
PULSES
4
FIELD 0
Figure 11.
ODD FIELD
1
2
FIELD 1
3
4
FIELD 0
AD9980
1