On Mon, 22 Aug 2005, Rainer.scherg wrote:
> Next question: ;-)
>
> looking on: * frontend.h (cvs 1.18)
>
> [...]
> typedef enum fe_type {
> FE_QPSK,
> FE_QAM,
> FE_OFDM,
> FE_ATSC
> } fe_type_t;
> [...]
>
> I do not understand FE_ATSC here,
> because QPSK, QAM QFDM are modulations.
> Why is FE_ATSC here?
In the same sense that there is FE_OFDM. COFDM uses QPSK, or QAM16 or
QAM64 modulations.
> ATSC supports several modulations...
> Shouldn't there be the modulation named (e.g. VSB)?
No, because an ATSC demodulator is capable of decoding VSB and QAM
signals.
QAM in the US is ITU J83 Annex-B. Europe's DVB is Annex-A. Asia is Annex
C.
> Next:
> Currently this is an enum field, but what happens
> if you are having a frontend supporting more than one modulation?
> (e.g. DVB-CT --> FE_QAM|FE_OFDM )
DVB-T is much too different to DVB-C. When this will happen, you'll
probably make two different frontend-dev-nodes with separate parts in
the one driver.
regards,
Patrick.
--
Mail: patrick.boettcher@xxxxxxx
WWW: http://www.wi-bw.tfh-wildau.de/~pboettch/
