On Tue, Nov 15, 2011 at 12:12 AM, Mauro Carvalho Chehab
<[email protected]> wrote:
> Em 14-11-2011 16:30, Manu Abraham escreveu:
>> On Mon, Nov 14, 2011 at 11:38 PM, Mauro Carvalho Chehab
>> <[email protected]> wrote:
>>> Yet, this doesn't require any changes at DVB API, as all that the
>>> demodulator
>>> need to know is the sub-carrier parameters (frequency, roll-off, symbol
>>> rate, etc).
>>
>> You do: this is why there were changes to the V3 API to accomodate
>> DVB-S2, which eventually became V5. The major change that underwent is
>> the addition of newer modulations. The demodulator need to be
>> explicitly told of the modulation. With some demodulators, the
>> modulation order could be detected from the PL signaling, rather than
>> the user space application telling it.
>
> DVB-S2 doesn't require DVB bandwidth to be specified.
stb0899:
switch (state->delsys) {
case SYS_DVBS:
case SYS_DSS:
......
if (state->config->tuner_set_bandwidth)
state->config->tuner_set_bandwidth(fe, (13 *
(stb0899_carr_width(state) + SearchRange)) / 10);
if (state->config->tuner_get_bandwidth)
state->config->tuner_get_bandwidth(fe,
&internal->tuner_bw);
.......
break;
case SYS_DVBS2:
......
if (state->config->tuner_set_bandwidth)
state->config->tuner_set_bandwidth(fe,
(stb0899_carr_width(state)
+ SearchRange));
if (state->config->tuner_get_bandwidth)
state->config->tuner_get_bandwidth(fe,
&internal->tuner_bw);
break;
cx24116:
/* Set/Reset B/W */
cmd.args[0x00] = CMD_BANDWIDTH;
cmd.args[0x01] = 0x01;
cmd.len = 0x02;
ret = cx24116_cmd_execute(fe, &cmd);
if (ret != 0)
return ret;
stv090x does a lot of auto detection for almost everything, but still:
stv090x:
if (state->algo == STV090x_COLD_SEARCH)
state->tuner_bw = (15 *
(stv090x_car_width(state->srate,
state->rolloff) + 10000000)) / 10;
else if (state->algo == STV090x_WARM_SEARCH)
state->tuner_bw =
stv090x_car_width(state->srate, state->rolloff)
+ 10000000;
}
Regards,
Manu
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