Analog back-end calibration

[AndreNe]

I generate a sine wave with the command line utility (for example: "generate 1 0.01 100 sine").
Now I measure the outgoing signal with a oscilloscope and see that the sine wave is not in the middle of zero.
I change the calibration coefficient "BE_CH1_DC_offs" with the calib -w command but the offset of the signal is not changed.
What do I wrong?

[redpitaya]

Hi,

You want to calibrate free applications?

Best, RP

[AndreNe]

Hi,
I don't use a application. I generate the signal with the command line.
Is the calibration only available if I generate a signal with a app?

[jerzydziewierz]

hi,
if you have a reference to calibrate against,
and use desktop tools like matlab or python,

it will be easiest for you to calibrate in post-processing (on desktop).

Otherwise you will find yourself reading source code of the FPGA.

[Nils Roos]

Otherwise you will find yourself reading source code of the FPGA.

Compensating signals for calibration is all done outside the FPGA at the moment.

I don't use a application. I generate the signal with the command line.
Is the calibration only available if I generate a signal with a app?

Your problem is that the generate tool is not programmed to use the calibration values. I never tire of recommending edgo's calibration-aware tools.

[AndreNe]

I found a solution to compensate the offset of the analog back end. I manipulate the fpga registers 0x40200004 for channel 1 and 0x40200024 for channel 2 with the monitor tool.

My next problem is that I need to to this every time I power up red pitaya.
Is it possible to to start a shell script after red pitaya finished the boot process.
I insert my command in the rcS file in opt/etc/init.d location but this dosen't work.
(/etc/init.d/rcS: /opt/etc/init.d/rcS: line 22: monitor: not found)

[AndreNe]

It was a failure of myself.
I forgot to give the path to execute command.
opt/bin/monitor 0x...