Albalá Ingenieros AVD0001C01, Manual

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Albalá Ingenieros | Manual AVD0001C01
4.2.1. DC restorer
The purpose of the DC restorer is to set the blanking level of the video signal to zero
volts. The two most common situations where DC restoration is necessary are when
the incoming video signal has some DC voltage superimposed on top of it and when
50/60Hz hum from the electrical network has coupled into the video signal. In the
first case the slow mode of operation should be used, for the second case the fast
mode should be used.
DC RESTORER CONFIGURED
IN FAST MODE
The AVD0001C01 comes from the factory with the DC restorer activated and set to
fast mode.
4.2.2. The equalizer
The equalizer is in charge of modifying the frequency response of the distributor to
compensate for the attenuation incurred as the video signal is transported over
coaxial cable to the input of the AVD0001C01. This is done only once, as the module
has a single input.
A waveform monitor or oscilloscope is required in order to observe the video signals at
the distributor outputs for modification of the frequency response of the equalizer.
While observing the signal the potentiometer is used to adjust the equalizer until the
desired signal waveform has been produced. Keep in mind that proper measurement
of the signal requires a cable that is terminated with 75Ω.
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