UPC1830GT NEC, UPC1830GT Datasheet - Page 13

• Manufacturer Part Number: UPC1830GT
• Description: FILTER-CONTAINING VIDEO CHROMA/ SYNCHRONIZING SIGNAL PROCESSING LSI COMPATIBLE WITH NTSC/PAL SYSTEM
• Manufacturer: NEC

5. BLOCK OPERATION
5.1 Video Signal Processing Section
(1) Input signal
(2) Clamp circuit
(3) Chroma trap circuit
(4) Separate/composite switching circuit
(5) Delay circuit
(6) Contrast adjustment circuit
Less than 3.7 V
3.7 V or higher
After coupling by a capacitor (0.22 F), a 1 V
pin (pin 36).
The clamp circuit controls the pedestal voltage level to be constant to make it a reference voltage for the post-stage
signal processing.
Eliminates the chroma signal (NTSC system: approximately 3.58 MHz, PAL system: approximately 4.43 MHz) from
a composite video signal and extracts a brightness signal.
Operates as shown in Table 5-1 according to the voltage of the separate chroma input pin (pin 34).
Separate chroma input
Compensates for the delay between the brightness signal and chroma signal by delaying the brightness signal.
Adjusts the amplitude of the brightness signal output from the Y output pin (pin 12) according to the voltage of the
contrast control pin (pin 38).
The control characteristic is shown in Figure 5-1.
pin (pin 34) voltage
Table 5-1. Operation when Switching Separate/Composite Signals
Y/C separate input
Composite video input
Mode
p-p
composite video signal is input to the composite video signal input
Without chroma trap
With chroma trap
Brightness signal
processing
Input from separate chroma
Input from chroma BPF
ACC amp input
PC1830
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