This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/osmocom-sdr@lists.osmocom.org/.
David Basden davidb-sdr at rcpt.toHmmm. You're right. My bad; I confused it with (I suspect) the E4000 VCO, and it really doesn't make sense given the wider channel bandwidth of a DVB signal. At 8 bits, 225 Msps isn't going to fit down USB2 though :( On Mon, Aug 19, 2013 at 08:47:20PM -0700, jdow wrote: > That doesn't necessarily square with "7-bit ADC for RF signals level > measurement". It's unclear to me where it would get the signal with > enough levels that a 7-bit ADC would get used. You'd have to decimate > down to 225 Msps or so in order to get 7 bits of data. > > {^_^} Joanne/W6MKU > > On 2013/08/19 20:17, David Basden wrote: > >The RTL2382U has an ADC onboard; The dongles don't use a seperate > >ADC. The main other component is the tuner. > > > >The RTL2382U uses a sigma-delta ADC, so it samples at a much higher > >rate than it needs, but only at 1 bit. It then trades the high > >sample rate for higher dynamic range. (Think reverse PWM, although > >that is a huge oversimplification). > > > > > >http://www.maximintegrated.com/app-notes/index.mvp/id/1870 > > > >The crystal is to drive the clock of the RTL2832U. It's almost certainly > >running a single 1 bit sample per clock. > > > >If you were to get the samples at the 28.8Msps rate, they would be 1 bit > >samples, which you would still have to filter and downsample for most > >uses. I'm not aware of any way to get the samples out at that rate. > > > >David > > > >On Mon, Aug 19, 2013 at 11:44:51PM -0300, Lucas Ingles wrote: > >>Hello to all, > >> > >>Please, can someone help me to understand how RTL2832U samples signals? > >>I know it has two ADCs, one for the I (in-phase) component and other ADC > >>for the Q (quadrature) component. > >> > >>In http://superkuh.com/rtlsdr.html the author states the signal is sampled > >>initially at 28.8 Msps and then re sampled to present whatever sample rate > >>is desired. > >> > >>But > >>http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=35&Level=4&Conn=3&ProdID=257 > >>says > >>that 28.8MHz is the frequency of the crystal, not the ADC. > >> > >>I am confused with that, can someone help me? > >>If RTL2832U is able to sample at 28.8Msps, why don't use the maximum sample > >>rate? Maybe USB limitations? > >> > >>Also, all ADCs used in RTL-SDR dongles are inside RTL2832U? Or we have > >>external ADCs? > >> > >>Thanks very much in advance, > >>Lucas Ingles > >