SVP DCM-1070, Руководство пользователя

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Chapter 1: VT-70 Modulator
VR-70 and DCM User’s Manual Page 15
It is important that 75 Ω connectors are used. This is because the female
output connector of the VR-70 demodulator unit may be damaged and
because an impedance mismatch will occur.
If the received RF signal does not carry a video signal, the display in the
demodulator unit will display VIDEO: OFF and the led next to the ALARM
button flashes red. This way the user knows that video signal is not been
inserted in the transmitted signal or that there might be a failure in the
video source and/or the connection cables. When input video signal is
detected, the led next to alarm button is switched off (if there are no more
alarms) and in the display appears VIDEO: ON.
2.3 Audio
The equipment is delivered with the output configuration below:
ƒ
Maximum line level +12dBm, balanced output on 600 Ω .
ƒ
Because the audio signal is balanced, its level is measured between 2
nd
and 3
rd
pins.
ƒ
The VR-70 has two audio outputs, available on 3-pin male XLR
connectors on the rear panel.
XLR-3 pinout is:
ƒ
PIN-1: ground
ƒ
PIN-2: hot (+)
ƒ
PIN-3: cold (-)
The equipment has an audio meter. To visualize the measurement, the
following option in the menu has to be selected: Monitor Status: Peak Level
Meter. The operation of this audio meter is similar to the operation mode of
a picometer, since it has different integration times for ascendant (fast) and
descendent (slow) slopes. This facility is useful to measure signal peaks,
not the signal level.
2.4 Up-Converter and Down-Converter
To connect the rack-mount VR-70 demodulator unit and the DCM down-
converter a low loss 50
Ω coaxial cable should be used.
If a RG-214 coaxial cable is used the maximum cable length is 100m. Cable
length can be doubled if celflex cable of ½” is used.
High quality 50
Ω N connectors are recommended in cable ends.