On 2021-10-23 5:58 p.m., Ivan Zahartchuk wrote:
I want to create FPGA firmware for USRP E310 with window function but
I get the error I described above. My yaml file is also attached
above. I need to do windowing and FFT on the FPGA side. And understand
why FFT returns zero values even when it is configured to produce
complex data.
There are two distinct problems described here. One is that for
very-small input values, the FFT produces zero outputs. This is very
likely due to the
fact that the FFT implementation in the FPGA is an integer
implementation, with fixed precision. If it's scaling the output
appropriately for
mag**2, there will be cases where it produces zeros. You can
either increase the RF gain, or, as I *THINK* you're trying to do, use
the window
function to artificially boost the input amplitudes prior to the FFT
computation?
Unfortunately, I don't personally have an RFNOC toolchain myself, so I
can't offer much in the way of advice on the build error you're getting,
and I'm
hoping someone with more RFNOC-on-E310 experience can be of more help.
image.png
пт, 22 окт. 2021 г. в 17:55, Marcus D. Leech <[email protected]
<mailto:[email protected]>>:
On 2021-10-22 6:05 a.m., Ivan Zahartchuk wrote:
Yes I am setting fft for magnitudes. On the front side, I am
doing a log. I perfectly understand where infinity comes from. I
don’t understand why the FFT returns 0. But how can I configure
the Window?
What does uhd_usrp_probe show in the "RFNOC Blocks" section on
this device?
I think the window RFNOC function in GNu Radio takes a list of the
window values as a parameter--you can populate that with any of
the window.* functions
within Gnu Radio.
пт, 22 окт. 2021 г. в 01:51, Marcus D. Leech
<[email protected] <mailto:[email protected]>>:
On 2021-10-21 6:40 p.m., Ivan Zahartchuk wrote:
Hello, I have a problem that when receiving samples from the
USRP E310 board, after the FFT block at low gain, zero
values are received. After that I log them and get infinity.
I wanted to figure out what the problem is, but I have no
idea, maybe the Window block will fix the situation. But
when building my yaml file, I get the error: [ERR] 2
Unresolved connection(s) [ERR] (window0-out_0 ->
fft0-in0) [ERR] (fft0-out_0 -> ep1-in_0) [INF]
(('radio0', 'ctrl_port', 'master'),) [INF]
(('radio0', 'time_keeper', 'listener'),) [INF]
(('radio0', 'x300_radio', 'slave'),) [INF]
(('_device_', 'ctrlport_radio', 'slave'),) [INF]
(('_device_', 'time_keeper', 'broadcaster'),) [INF]
(('_device_', 'x300_radio', 'master'),) Please tell me what
could be the problem and how can I add the Window block to
my image?
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Do you have your FFT configured for log output? Because the
logarithm of zero is undefined.
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