Re: LimeSDR Mini 2.4, Rx degradation with GR

Hi Dave,

I'm not an expert on the Lime hardware, but I could see how different filter, gain etc
configurations would lead to different performance. Can you explain what exactly you mean
with "degraded performance"?

Best,
Marcus

On 4/10/25 6:59 AM, dave_abel@bigpond.com wrote:
> I have a LimeSDR Mini 2.4.When I test Rx performance using the LimeSuiteGUI, I see
> performance in line with the device specifications.With GNU Radio 3.10.1.1 under Ubuntu
> 22.04.5, the performance is severely degraded.The GR test is a simple flowgraph of a Soapy
> LimeSDR Sink into a QT GUI Sink.
>
> The relevant snippet from the generated Python code ls:
> ********************************************
>
>         self.soapy_limesdr_source_0 = None
>         dev = 'driver=lime'
>         stream_args = ''
>         tune_args = ['']
>         settings = ['']
>
>         self.soapy_limesdr_source_0 = soapy.source(dev, "fc32", 1, 'soapy=0,driver=lime',
>                                   stream_args, tune_args, settings)
>         self.soapy_limesdr_source_0.set_sample_rate(0, samp_rate)
>         self.soapy_limesdr_source_0.set_bandwidth(0, 5000000)
>         self.soapy_limesdr_source_0.set_frequency(0, freq)
>         self.soapy_limesdr_source_0.set_frequency_correction(0, 0)
>         self.soapy_limesdr_source_0.set_gain(0, min(max(gain, -12.0), 61.0))
> ***************************************************
>
>
>
> The GR console log suggests that something is being lost in transit.
>
>
> **********************************************************************
>
> Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on
> Wayland anyway.
>
> [INFO] Make connection: 'LimeSDR Mini [USB 3.0] 1DA13CDBCB3B1C'
>
> [INFO] Reference clock 40.00 MHz
>
> [INFO] Device name: UNKNOWN
>
> [INFO] Reference: 40 MHz
>
> [INFO] LMS7002M register cache: Disabled
>
> [INFO] RX LPF configured
>
> [INFO] RX LPF configured
>
> [INFO] Rx calibration finished
>
> ******************************************************************
>
>
> Soapy recognises the device.
>
> *****************************************************
>
> dave@dave-Inspiron-3020:~$ SoapySDRUtil --info
>
> ######################################################
>
> ##Soapy SDR -- the SDR abstraction library##
>
> ######################################################
>
>
> Lib Version: v0.8.1-g6e99da18
>
> API Version: v0.8.200
>
> ABI Version: v0.8-3
>
> Install root: /usr/local
>
> Search path:/usr/local/lib/SoapySDR/modules0.8-3
>
> Module found: /usr/local/lib/SoapySDR/modules0.8-3/libLMS7Support.so (23.11.0-b39cb61e)
>
> Available factories... lime
>
> Available converters...
>
> -CF32 -> [CF32, CS16, CS8, CU16, CU8]
>
> -CS16 -> [CF32, CS16, CS8, CU16, CU8]
>
> -CS32 -> [CS32]
>
> -CS8 -> [CF32, CS16, CS8, CU16, CU8]
>
> -CU16 -> [CF32, CS16, CS8]
>
> -CU8 -> [CF32, CS16, CS8]
>
> -F32 -> [F32, S16, S8, U16, U8]
>
> -S16 -> [F32, S16, S8, U16, U8]
>
> -S32 -> [S32]
>
> -S8 -> [F32, S16, S8, U16, U8]
>
> -U16 -> [F32, S16, S8]
>
> -U8 -> [F32, S16, S8]
>
> ***********************************************
>
>
> dave@dave-Inspiron-3020:~$ SoapySDRUtil --find
>
> ######################################################
>
> ##Soapy SDR -- the SDR abstraction library##
>
> ######################################################
>
>
> Found device 0
>
> addr = 24607:1027
>
> driver = lime
>
> label = LimeSDR Mini [USB 3.0] 1DA13CDBCB3B1C
>
> media = USB 3.0
>
> module = FT601
>
> name = LimeSDR Mini
>
> serial = 1DA13CDBCB3B1C
>
> ***************************************************
>
>
> Any advice on how to proceed, please?
>
>
> Thanks
>
>
> Dave
>
>
>
>