[linux-dvb] [PATCH] Fix the min/max frequencies of some DVB-C frontends

Manu Abraham abraham.manu at gmail.com
Tue Aug 7 00:54:50 CEST 2007


On 8/7/07, Trent Piepho <xyzzy at speakeasy.org> wrote:
>
> Most demodulators don't have frequency ranges.  They just take whatever the
> tuner gives them at a fixed intermediate frequency.  It's really the tuner
> that has the frequency range.


Not true: look at the MB86A16. It is a DC (Direct Conversion)
receiver. There is no tuner used alongwith (a similar case goes for
the MB86A15, but that is far from being similar) and hence no IF. But
in either case, absolutely _no_ tuner.

There are other DC receivers as well, mentioned the MB86A16 as an
example, since being more familiar with it.


> I think it would make more sense for the demodulator drivers to fill
> fe->ops.info.frequency_min|max using fe->ops.tuner_ops.info.frequency_min|max.
> A frontend driver that doesn't use a separate tuner driver (like DST) would
> set the fe->ops.info.frequency_min|max directly.


DST, inside the host CPU, does calculations based on the upper and
lower bounds, but that generally results in almost the same defined
spectral definition according to the standards.


Manu



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