Re: Ynt: Spectrum Analyzer

On 22/03/2025 05:57, Marcus Müller wrote:
> It sounds you have a USRP B2xx  (USRPs are very different, just saying
> "USRP" says little).
>
>
> For a limited numbers of frequencies you tune to, you can program the
> AD9361 to "know" the physical parameters of the tuning, and hop
> between these frequencies.
>
> But two obstacles:
>
> - that number is too small to build a scanner with it
> - you would need to circumvent most of UHD's tuning logic, so this
> would be a fundamental rewrite of your application, modifying your
> version of UHD, probably replacing the UHD USRP Source, and probably
> changing the overall logic flow.
>
> So, no, in all practical terms, since you simply can't preprogram the
> properties for all your hops, you will have to let the hardware take
> as long as it takes.
>
> Best regards,
> Marcus
>
In general, the synthesizers for general-purpose radios aren't optimized
for very-fast tuning.   The AD9361 is slower than
  many others, due to calibration algorithms it runs when re-tuning.

Things like fast-sweeping spectrum analyzers and frequency-hopping
radios typically use a PLL synthesizer that is optimized
  for very-fast re-tunes, but sacrifices things like phase-noise to
achieve it.

In an SDR environment, even if the synthesizer were blazing fast at
re-tuning, you're still limited by the command latency
  to a certain extent (although with 'tricks' like timed commands, you
can stack them up in advance a little bit).


> On 3/21/25 4:35 PM, Oğuzhan Gedikli wrote:
>> Hi,
>>
>> Actually, I have already created the code. I can scan the entire band
>> with a switch algorithm. Or I can perform a scan according to the
>> frequency ranges I enter.
>>
>> Thank you for the information that the bandwidth is 56MHz regardless,
>> this was really valuable information and explains why frequency
>> switches at short distances, actually within 56 MHz, also take a
>> short time.
>>
>> What I am really curious about is, is there any way to speed up the
>> frequency switch of this board? I accept responsibility for all
>> unsafe ways.
>>
>> Kind regards,
>> ------------------------------------------------------------------------------------------
>>
>> *Gönderen:* Anıl Gürses <anilgurses98@gmail.com>
>> *Gönderildi:* 20 Mart 2025 Perşembe 19:30
>> *Kime:* Oğuzhan Gedikli <ouzan_ts@hotmail.com>
>> *Bilgi:* discuss-gnuradio@gnu.org <discuss-gnuradio@gnu.org>
>> *Konu:* Re: Spectrum Analyzer
>> Hi Oğuzhan,
>>
>>     My main goal is to create a spectrum that I can look at between
>> 70mhz - 6ghz. When I
>>     set the bandwidth to 6ghz, i can actually see it in a window, but
>> the sample rate of
>>     my card is 56mhz. So wouldn't the maximum bandwidth I can see be
>> 56 mhz?
>>
>> QT GUI sink's bandwidth parameter is used for setting x-axis labels
>> similar to the center frequency parameter. Therefore, the plot you
>> see has 56 MHz bandwidth with wrong x-axis labels. Ref ->
>> https://wiki.gnuradio.org/index.php/QT_GUI_Frequency_Sink <https://
>> wiki.gnuradio.org/index.php/QT_GUI_Frequency_Sink>
>>
>>     Another Question: Can i build a 6ghz spectrum analyzer on
>> gnuradio without writing any
>>     frequency switch algorithm?
>>
>> You can't. Sweeping the frequencies at a very fast pace presents a
>> performance bottleneck. You can use stream-to-vector,
>> vector-to-stream, and Python blocks to combine samples from different
>> frequencies. Before applying stream-to-vector, you need to upconvert
>> the collected signal. Afterward, you can feed it into the QT GUI
>> sink. However, processing all those samples will take considerable
>> time, especially given the 6GHz bandwidth sweep. This is just a
>> simple, generalized implementation and may omit some steps.
>>
>> Respectfully,
>> A.
>>
>> On Thu, Mar 20, 2025 at 7:07 AM Oğuzhan Gedikli <ouzan_ts@hotmail.com
>> <mailto:ouzan_ts@hotmail.com>> wrote:
>>
>>     Hello,
>>
>>     I want to make a spectrum analyzer. i have a USRP. I did this
>> using QT GUI Range.
>>
>>     My main goal is to create a spectrum that I can look at between
>> 70mhz - 6ghz. When I
>>     set the bandwidth to 6ghz, i can actually see it in a window, but
>> the sample rate of
>>     my card is 56mhz. So wouldn't the maximum bandwidth I can see be
>> 56 mhz?
>>
>>     Another Question: Can i build a 6ghz spectrum analyzer on
>> gnuradio without writing any
>>     frequency switch algorithm?
>>
>>     Kind regards,
>>
>
>