AOC Vibrant VL7A9DA Service Manual page 47

Figure 3 below shows the main functional blocks inside the gmZAN1
2.1 Overall Architecture
Analog
Triple
RGB ADC
MCU
2.2 Clock Recovery Circuit
The gmZAN1 has a built-in clock recovery circuit. This circuit consists of a digital clock synthesizer and an analog
PLL. The clock recovery circuit generates the clock used to sample analog RGB data (SCLK or source clock). This
circuit is locked to the HSUNC of the incoming video signal. The RCLK generated from the TCLK input is used as a
reference clock.
The clock recovery circuit adjusts the SCLK period so that the feedback pulse generated every SCLK period
multiplied by the Source Horizontal Total value (as programmed into the registers) locks to the rising edge of the
Hsync input. Even though the initial SCLK frequency and the final SCLK frequency are as far apart as 60MHz ,
locking can be achieved in less than 1ms across the operation voltage/temperature range.
2. FUNCTIONAL DESCRIPTION
Figure 3. Block Diagram for gmZAN1
Source
Timing
Measurement
/ Generation
Host
Interface
On-Screen
Display
Control
Scaling Gamma
Control
Engine
(CLUT)
+
Dither
Clock
Recovery
Clock
Reference
Panel
Timing
Panel
Control
Pixel
Clock
Generator