AD9983A/PCBZ Analog Devices Inc, AD9983A/PCBZ Datasheet - Page 17

• Manufacturer Part Number: AD9983A/PCBZ
• Description: Pb-free EVALUATION Kit AD9983A
• Manufacturer: Analog Devices Inc
• Series: Advantiv®r

Specifications of AD9983A/PCBZ

• Main Purpose: Video, Video Processing
• Embedded: No
• Utilized Ic / Part: AD9983A
• Primary Attributes: 3 x 8-Bit 140 MSPS ADC's
• Secondary Attributes: Integrated PLL & VCO
• 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 shifting it in time slightly.
The goal is to keep the Vsync and Hsync leading edges from
switching at the same time, thus eliminating confusion as to
when the first line of a frame occurs. Register 0x14, Bit 2
enables the Vsync filter. Use of the Vsync filter is recommended
for all cases, including interlaced video, and is required when
using the Hsyncs per Vsync counter. Figure 11 and Figure 12
illustrate 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
QUADRANT
VSYNCOUT
VSYNCOUT
O/E FIELD
O/E FIELD
HSYNCIN
VSYNCIN
HSYNCIN
VSYNCIN
EXPECTED
EDGE
2
2
FIELD 1
FIELD 1
SYNC SEPARATOR THRESHOLD
SYNC SEPARATOR THRESHOLD
EQUALIZATION
Figure 12. Vsync Filter—Even Field
Figure 11. Vsync Filter—Odd Field
3
3
PULSES
4
4
FIELD 0
FIELD 0
EVEN FIELD
ODD FIELD
1
1
2
2
FIELD 1
FIELD 1
3
3
AD9983A
4
4
FIELD 0
FIELD 0
1
1