Okay, I think I understand well enough now. Thanks, Andrew!

Thanks, Andrew!

Let me also add that the issue with not being able to drop the span to less than 500 kHz without it crashing has also been fixed!

Here ya go. Here’s the set-up. Trace One is running “Clear-Write”, while Trace Two is running MAX HOLD. The “original” file is with a center frequency of 123.05 MHz. The “changed” file is with a new center frequency of 123.2 MHz. Trace Two has not changed.

Attachments:

You must be logged in to view attached files.

Surely. Here’s the information straight from the “System” report:
CPU: Topology: Quad Core model: Intel Core i7-6700 bits: 64 type: MT MCP arch: Skylake-S
rev: 3 L2 cache: 8192 KiB
flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 54398
Speed: 800 MHz min/max: 800/4000 MHz Core speeds (MHz): 1: 800 2: 800 3: 800 4: 800
5: 801 6: 800 7: 800 8: 800

Okay. Thanks, Justin.

Hey, Kefei Hei, I may be able to help you (assuming you’ve not already figured it out). I’m using Gnu Octave, not Matlab, but they should be fairly similar. On my computer (an Intel-based system), the Signalhound IQ data shows up as “shorts”.

I created an IQ file called “myFile.iq”. Here’s a short script I created to read in a short bit of data from that IQ file, then generate a simple FFT display (no windowing).

f=fopen('myFile.iq','rb'); % Opens the file to read as binary data.
s=fread(f,8192,'short'); % Reads in 8192 samples.
% Signalhound IQ data is a stream of I-Q-I-Q... points.
% It must be parsed out to properly represent the data.
sReal=s(1:2:end); % Set the real points
sImag=s(2:2:end); % Set the imaginary points
sc=sReal+j*sImag; % Create the actual complex samples
frq=20*log10(abs(fft(sc/8192))); % Create FFT
frqShift=fftshift(frq); % Shift the horizontal axis so that it displays properly
plot(frq)

Note that, if I left out the “8192” from the “fread” statement, it would have read all of the data at once.

I tested this, and the spectrum I got was similar to what I got from Spike, so I believe I have the set-up correct.

Hope this helps!

[Gary]

Ah! Got it! Thank you, Andrew!

• This reply was modified 5 years, 5 months ago by Gary.

Thank you for the response. I’m confused, however. According to the Signalhound API manual, you use the 3 dB points to create the variable-width RBWs. But the value “2.02” for the Nuttall also matches the value for the table at the end of the API manual. That is the ENBW. The 3 dB value, according to my calculations, is around 1.9 bins for your Nuttall.
Any idea what I’m misunderstanding?

[Gary]

UPDATE: SUCCESS! Turned out I needed to load “swig” (available in Software Manager). Once I did that, then went through the process from “cmake ..” on down, I opened GRC, ran the flowgraph, and it worked!

Once I summarize my notes (they’re, uh, kinda messy), I’ll post another thread explaining how I did it.

Thanks, again!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Long story short: I had tried to install Gnu Radio from source and with Pybombs, both of which gave me more errors than did the BB60C “cmake..” command. I followed your links and the answer was to install “gnuradio-dev”.
However, even with that, I kept getting:

/sbin/ldconfig.real: /usr/local/lib/libftd2xx.so is not a symbolic link

/sbin/ldconfig.real: /usr/local/lib/libbb_api.so.4 is not a symbolic link

after the “sudo ldconfig” command.

I thought it might still work, so I opened Gnu Radio Companion and added the “BB60C: IQ Source”. However, when I attempted to run the simple flowgraph (it was simply attached to a frequency sink to look at the spectrum), I got the following errors in GRC:

Generating: '/home/gary/gnuradio/bb60SpectrumAnalyzer.py'
>>> Warning: This flow graph may not have flow control: no audio or RF hardware blocks found. Add a Misc->Throttle block to your flow graph to avoid CPU congestion.

Executing: /usr/bin/python -u /home/gary/gnuradio/bb60SpectrumAnalyzer.py

Warning: failed to XInitThreads()
qt5ct: using qt5ct plugin
Traceback (most recent call last):
  File "/home/gary/gnuradio/bb60SpectrumAnalyzer.py", line 156, in <module>
    main()
  File "/home/gary/gnuradio/bb60SpectrumAnalyzer.py", line 144, in main
    tb = top_block_cls()
  File "/home/gary/gnuradio/bb60SpectrumAnalyzer.py", line 116, in __init__
    self.bb60c_source_0 = bb60c.source(1e9, -20, -1, -1, 2, samp_rate, False, False, 0, 0)
AttributeError: 'module' object has no attribute 'source'
inotify_add_watch("/home/gary/.config/qt5ct") failed: "No such file or directory"

I don’t know if those two issues are related.

Thank you for the help. I think I’m pretty close to making this work. Once I do, I’ll do a short write-up explaining to others how I got it to work in Mint 19.1.

• This reply was modified 5 years, 8 months ago by Gary.

[Gary]

I’m going to second this. I bought two, different types of USB-C to USB micro-B 3.0 cables from Amazon. I’m testing the first one now on my BB60C. I’ve had it jumping between swept, real-time and zero span for about 45 minutes, all with no issues. Of interest is that this cable is a 2 meter one to give me maximum flexibility in setting up my BB60C in relation to the laptop controlling it.
I’ve dealt with the BB60C when it was on the ragged edge of not having enough power. You’d hear it as it dropped off from the USB, then come back. Again, no such issues here. Assuming the other cable is just as effective, I now have backups in case on cable gets damaged or broken.
I cannot speak of the interference issues, however. Right now, I’m surrounded by so much active electronics it would be difficult to specify if any interference was coming from the cable, or coming from one of the many, other electronic devices active near me.

• This reply was modified 5 years, 9 months ago by Gary. Reason: Added that the cable was 2 meters long

Great! Thanks, Andrew!

Thanks, Andrew. I was using a laptop with a touchpad. I’ll have to add a mouse for this reason.

That did it! Thank you! I saved my pennies for two years to get one of these, and it’s been a very worthwhile purchase. I’ll be looking forward to the next version of the software.

P.S. I’d like to recommend that the spectrogram also be paused when unchecking the “Update” box.

[Author]

Posts