Black Box AC043A-R2, Инструкция по эксплуатации, Страница: 10 / 14

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CHAPTER 4: Configuration and Operation
4. Configuration and Operation
The Video Splitter-8 usually operates unattended. It will continuously relay any
received input signal to all connected output devices (monitors, video recorders,
etc.). However, it does have two sets of controls that affect the
way it operates:
calibration and AGC controls in front plus a DC restore/clamp switch in the rear.
4.1 The Gain Controls and LED
The AGC (automatic gain control) switch, CAL (calibration) switch, GAIN knob,
and “GREEN = UNITY GAIN” LED are on the Video Splitter-8’s front panel, as
shown in Figure 4-1 on the next page. Here’s how these components determine
and indicate the Splitter-8’s video handling, assuming an NTSC video input:
• With the CAL and AGC switches both ON, the LED is always lit and the knob
has no effect. The AC043 models maintain a constant S-Video output level of
Y = 1 Vpp, C = 288 mVpp. The AC044 models maintain a constant composite-
video output level of 1 Vpp.
• With the CAL switch ON and the AGC switch OFF, the LED is always lit and
the knob has no effect. Output levels follow input levels (Vout = Vin, unity
gain); in this setting, the Splitter-8 doesn’t amplify the input signal before
retransmitting it to the output equipment.
• With the CAL switch OFF and the AGC switch ON, the knob determines the
output level regardless of the input level. For the AC043 models, output can
range from Y = 0.5 Vpp, C = 144 mVpp (with the knob as far as it can go
counterclockwise) to Y = 1.5 Vpp, C = 432 mVpp (with the knob as far as it can
go clockwise). The LED lights when Vout = 1 Vpp, which should occur when
the knob is approximately at its central point.
• With the CAL and AGC switches both OFF, the output level will equal the
input level multiplied by the gain selected with the knob (Vout = gain x Vin).
Amplification can range from –6 dB (input signal halved, with the knob as far
as it can go counterclockwise) to +6 dB (input signal doubled, with the knob as
far as it can go clockwise). The LED lights when gain = 1 (unity gain), which
should occur when the knob is approximately at its central point.