[vdr] Re: HF-Modulator

[Tobias Haustein <haustein@aixmail.de>]

* Brian Dorling (Brian_Dorling@t-online.de) [040113 22:31]:

> Tobias,
> where did you get the info about the other components that are needed to 
> build the complete modulator?

That's quite simple. The video signal line must be closed using an resistor
of 75 Ohm, and the video signal is passed to the HF modulator through a 
capacitor of (as far as I recall) 4.7 uF. The audio signal is also coupled 
through a capicator in order to remove the direct current component.


                        4.7 uF

                         ||
Video + o----+-----------||-----o HF modulator video in
             |           ||
             #
             # 75 Ohm
             #
             |
Video - o----+------------------o HF modulator ground
             |
Audio - o----+

             ||
Audio + o----||-----------------o HF modulator sound in
             ||

            4.7 uF


I'm not absolute sure about the capacities, but the exact values are not that 
crucial anyway. If things don't work, try a bit or have a look into any
handbook on video electronics.


Ciao,

Tobias

-- 
Tobias Haustein

E-Mail tobias.haustein@aixmail.de


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