Thanks, Josh.
How can I specify the peak from GRC generated Python code? For example,
when I select the sc8 wire format, the following code is generated through
GRC.
stream_args=uhd.stream_args(
cpu_format="fc32",
otw_format="sc8",
channels=range(1),
),
If I want to limit the peak to 0.1 (if the received signal is very weak),
can I just use the following?
stream_args=uhd.stream_args(
cpu_format="fc32",
otw_format="sc8",
peak = 0.5,
channels=range(1),
),
Thanks,
Nazmul
On Thu, Jul 26, 2012 at 8:15 PM, Josh Blum <j...@ettus.com> wrote:
>
>
> On 07/26/2012 05:09 PM, Nazmul Islam wrote:
> > Hi Josh,
> >
> > I am just wondering how the USRP performs the 8 bit mapping for I & Q
> > samples. The ADC & DAC have 12 - 14 bit precision, I think. When I select
> > the sc8 wire format, does the USRP divide the entire received signal
> range
> > into 2^8 sectors and uses one number to represent each of those?
> >
>
> Technically, there is just a multiply and slice operation. You can
> specify peak to optimize for the best use of t 8 bits of dynamic range.
> See:
>
> http://files.ettus.com/uhd_docs/doxygen/html/structuhd_1_1stream__args__t.html#a4463f2eec2cc7ee70f84baacbb26e1ef
>
> -josh
>
> > Thanks,
> >
> > Nazmul
> >
> > On Sun, Jul 22, 2012 at 4:22 PM, Josh Blum <j...@ettus.com> wrote:
> >
> >>
> >>
> >> On 07/22/2012 01:14 PM, Nazmul Islam wrote:
> >>> Hello,
> >>>
> >>> I am trying to use the complex int16 option of the UHD (source/sink)
> >>> blocks in my GRC generated python codes. I am doing wide band spectral
> >>> analysis in my experiments. Therefore, 50 MS/s will be very helpful for
> >> me.
> >>>
> >>
> >> The host format and the wire format are totally independent options
> >> here. Both of these properties also configurable properties in the GRC
> >> USRP source/sink blocks.
> >>
> >> * You need to set the wire format to sc8 (thats 2 bytes per complex
> >> sample) to achieve 50 Msps over gigabit ethernet.
> >>
> >> * The desired host format does not have to change. fc32 (complex floats)
> >> is a perfectly valid setting
> >>
> >> -josh
> >>
> >> _______________________________________________
> >> Discuss-gnuradio mailing list
> >> Discuss-gnuradio@gnu.org
> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >>
> >
> >
> >
>
--
Muhammad Nazmul Islam
Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.
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