On Tue, Jan 14, 2014 at 5:50 PM, <[email protected]> wrote: > Hi, > > > On 2014-01-14 15:23, Jiao Xianjun wrote: > >> Is there any information or hint on the settling time after new >> frequency set to dongle? >> > > That depends a bit on the tuner and the sample FIFO of the RTL2832, > but you need to drop a few buffers, as the PLL of the tuner takes > some time to lock and stabilize. > > Sample FiFO should be full at all times in a DVB-T. I have never seen it empty due to interfernce, noise, etc.
> > Can I immediately read samples after new frequency is set by >> rtlsdr_set_center_freq? If so, will the samples quality be degraded? >> > > Kyle Keen did some experiments for his scanning application > (rtl_power), and he settled for waiting a few milliseconds and > flushing the buffer to get optimal results. See here: > > http://cgit.osmocom.org/rtl-sdr/tree/src/rtl_power.c#n626 > > Regards, > Steve > > That's a little too long, making large spectrum tuners inoperable. In my scanner I use a read immediately after the frequency set without any problems. Of course I cannot vouch for correct frequency, but I have noticed that the frequency doesn't drift appreciably when resetting frequency and locking to a band. BR, Nikos
