FMComms2/3/4 Source issue

I cannot repeat this behavior. What firmware version are you using?

-Travis

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The latest I can find, V0.35. Also tested with V0.34 and get the same.

To confirm my setup, I have TX1 linked to RX1 via a 20dB attenuator and TX2 linked to RX2 via a 30dB attenuator.

Please see screenshots below.

I tested my setup with a python script (see attached) using pyadi-iio and this does not seem to have the described issue, ie both RXGains can be changed independently of one another.

pluto_tx2rx2.zip

Can you read out the hardware gain settings:

iio_attr -u ip:pluto.local -i -c ad9361-phy voltage0 hardwaregain

iio_attr -u ip:pluto.local -i -c ad9361-phy voltage1 hardwaregain

After the flowgraph as started.

-Travis

After the flowgraph is started,
    iio_attr -u ip:pluto.local -i -c ad9361-phy voltage0 hardwaregain
    43.000000 dB
    iio_attr -u ip:pluto.local -i -c ad9361-phy voltage1 hardwaregain
    43.000000 dB

Then after adjusting rx_gain1 to 45,
    iio_attr -u ip:pluto.local -i -c ad9361-phy voltage0 hardwaregain
    45.000000 dB
    iio_attr -u ip:pluto.local -i -c ad9361-phy voltage1 hardwaregain
    45.000000 dB

Then after adjusting rx_gain2 to 40,
    iio_attr -u ip:pluto.local -i -c ad9361-phy voltage0 hardwaregain
    45.000000 dB
    iio_attr -u ip:pluto.local -i -c ad9361-phy voltage1 hardwaregain
    45.000000 dB

Can you provide the generate flowgraph python file and the output of: iio_info -u pluto.local

-Travis

travisfcollins said:

Can you provide the generate flowgraph python file

It never occurred to me to look at the generated python file. Once I did, I could see where the problem is and was able to fix the behavior by creating a copy and editing the copy (see fmcomms234_pluto_test_fixed.py).

diff -Naur fmcomms234_pluto_test.py fmcomms234_pluto_test_fixed.py

--- fmcomms234_pluto_test.py    2022-11-03 00:28:31.228720243 +0200
+++ fmcomms234_pluto_test_fixed.py      2022-11-03 01:55:56.005431324 +0200
@@ -958,6 +958,7 @@
 
     def set_rx_gain2(self, rx_gain2):
         self.rx_gain2 = rx_gain2
+        self.iio_fmcomms2_source_0.set_gain(1, self.rx_gain2)
 
     def get_rx_gain1(self):
         return self.rx_gain1
@@ -965,7 +966,6 @@
     def set_rx_gain1(self, rx_gain1):
         self.rx_gain1 = rx_gain1
         self.iio_fmcomms2_source_0.set_gain(0, self.rx_gain1)
-        self.iio_fmcomms2_source_0.set_gain(1, self.rx_gain1)
 
     def get_q2(self):
         return self.q2

Please see zip file containing original flowgraph, generated python file, fixed python file and diff file.

2313.fmcomms234_pluto_test.zip

travisfcollins said:

and the output of: iio_info -u pluto.local

iio_info -u pluto.local
Library version: 0.24 (git tag: v0.24)
Compiled with backends: local xml ip usb
Unable to create IIO context pluto.local: Function not implemented (38)

This looks like a gnuradio bug and not specific to gr-iio. I created a bug report here: https://github.com/gnuradio/gnuradio/issues/6333

-Travis