[linux-dvb] ATSC card with 2 RF inputs.

Mac Michaels wmichaels1 at earthlink.net
Fri Jul 15 05:12:14 CEST 2005


I am unable to answer this question after reading the DVB 
API so I need some guidance.

The DViCO FusionHDTV 3 Gold-Q card had two RF input 
connectors and the ability to select either one of them.  
There is no difference between the capabilities of the RF 
connectors. How does the application program select one or 
the other of these connectors, by that I mean what DVB API 
call is used by the application program? v4l handles this 
as another input. Does DVB support something like an 
antenna switch that might be an appropriate model for this 
situation?

I do have a proposed solution, but I don't really like it.

First some background. The Windows software provided by the 
card manufacturer pretends that the two inputs have 
different characteristics. It uses OTA and Cable in the 
provided interface program to select both the tuner channel 
frequency table and corresponding RF input. It makes some 
sense in that one RF connector is labeled ANT and the other 
is labeled CABLE.

I prefer a general purpose interface so that either input 
can be used with either VSB or QAM. This is because cable 
TV can use either VSB or QAM. My proposed solution is to 
modify the current lgdt3302 driver to select the ANT input 
when 8VSB is selected or the CABLE input when QAM64 / 
QAM256 is selected. This is a small change.

I look forward to getting your feedback on this.

--Mac




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