On Mon, 22 Aug 2005, Rainer.scherg wrote:
> Patrick Boettcher schrieb:
>> On Mon, 22 Aug 2005, Rainer.scherg wrote:
>
>>> typedef enum fe_type {
>>> FE_QPSK,
>>> FE_QAM,
>>> FE_OFDM,
>>> FE_ATSC
> [...]
>>
>>> 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.
>
> OK, but querying GET_INFO from frontend.
> I cannot decide directly whether to use
> struct dvb_frontend_parameters {
> struct dvb_qam_parameters qam;
> struct dvb_vsb_parameters vsb;
>
> In this case I have to crosscheck capabilities,
> (which would make fe_type obsolete, because I
> always could check for capabilities only).
Aah, now I see your problem:
So, no you must not fill or read dvb_qam_parameters when passing it to a
FE_ATSC frontend. If you want to tune to a QAM signal with an FE_ATSC you
have to set vsb.modulation to QAM_256. Just like when you would tune to
QPSK when setting up a COFDM-frontend.
Only the vsb-field is handled by FE_ATSC.
HTH,
Patrick.
--
Mail: patrick.boettcher@xxxxxxx
WWW: http://www.wi-bw.tfh-wildau.de/~pboettch/
