Table of Contents
Advertisement
Scart Signals:
• Audio signals
0.5V RMS, <1K output impedance, >10K input impedance.
• Red, Green, Blue
O.7 Vpp ±2dB, 75R input and output impedance. Note that the Red connection
(pin20) can alternatively carry the S-Video Chrominance signal, which is 0.3V.
• Composite Video / CSync
1 Vpp including sync, ±2dB, 75R input and output impedance. Bandwidth = 25Hz to
4.8MHz for normal TV Video de-emphasis to CCIR405.1 (625-line TV)
Fast Blanking
75R input and output impedance. This control voltage allows devices to over-ride the
composite video input with RGB inputs, for example when inserting closed caption text. It is
called fast because this can be done at the same speeds as other video signals, which is why
it requires the same 75R impedances.
• 0 to 0.4V: TV is driven by the composite video input signal (pin 19). Left unconnected, it
\s pulled to 0V by its 75R termination.
• 1V to 3V: the TV is driven by the signals Red, Green, Blue and composite sync. The
latter is sent to the TV on pin 19. This signal is useful when using a TV to display the
RGB output of devices such as home computers with TV-compatible frame rates. Tying
the signal to 5V via 1 DDR forms a potential divider with the 75R termination, holding
the signal at around 2V. Alternatively, if a TTL level (0 to 5V) negative sync pulse is
available, this will be high during the display periods, so this can drive the blanking
signal via a suitable resistor.
Control Voltage
0 to 2V = TV, Normal.
5 to 8V = TV wide screen
9.5 to 12V = AV mode
11. CIRCUIT DESCRIPTION
11.1 POWER SUPPLY:
• Socket PL800 is the220VAC input.
• 3.15A fuse F1 is used to protect the device against short circuit.
•Voltage is rectified by using diode D805 and capacitor C815 (330uF) a DC voltage is
produced. (310-320V DC).
Advertisement
Table of Contents
