[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] BER Example - With QT Gui Chooser for Different M

From: Luis Felipe Albarracin Sanchez
Subject: Re: [Discuss-gnuradio] BER Example - With QT Gui Chooser for Different Modulations Issue
Date: Sun, 27 Jan 2019 22:03:05 -0500

Hello Cinaed,

Thank you so much for all the work in the BER, i tested both of the flowgraphs and they are very accurate regarding the BER measurements, i have a couple of questions if you don´t mind:

1- In the latest flowgraph you sent (my-ber-test.grc from Jan 25th) how do you change the modulations in the chunks to symbols block, in the flowgraph you sent me the flowgraph table was fixed with the values of "-1, 1", what line of commands should be place there to switch to other modulations?

2- The BER measurements you sent me seem so accurate,  I wonder if you could take a look at the flowgraph i sent you (my_ber_simulation_LFA.grc), what i did there was connecting a QT GUI Chooser to the functions i thougth would change the constellation selected,  do you have any ideas why  my change is not working, when i change in the QT GUI Chooser?, i would appreciate your help regarding this.

3- Attached is a flowgraph i have devloped for doing modulations up to 64 QAM, please take a look at it, and if you have any ideas on how i would make a good BER measurement of higher modulations (32 -QAM and 64-QAM) please let me know. To select the modulatios, the easiest way is to define in the default value of the QT GUI chooser the value of 3 (for 32-QAM) and the value of 4 (for 64 QAM).

Once again thanks a lot for all the help.

Kind regards.

On Fri, Jan 25, 2019 at 3:20 PM Cinaed Simson <address@hidden> wrote:
It bothered me that the random source wasn't working.

So I took at it again last night and discovered I needed to unpack a bit
from the random source stream.

Using the random source, the following work:


using the pull down menu.

There is, however, one caveat: for 8PSK you have to enable the complex
Multiply Const by -1 block after the Chunks to Symbols block.

Alternatively, you could change Chunks to Symbols from -1,1 to 1,-1 -
but that's many more key strokes then just enabling and disabling the
Multiply Const block.

They all work with the GLFSR source too and with the same caveat.

And you were right you don't need the PSK symbol table - you can use
Chunks to Symbols -1,1 (except for 8PKS.)

Also, I had to add a unpack k=1 block after the decoder - otherwise for
DPSK, 8PSK and 16QAM there was a vertical offset and BER sky rockets.

The unpack k=1 is not needed for BPSK and QPSK - but it doesn't create
any problems so I left it enabled.

You just need to add the complex noise source

Have fun with QT.

Actually, there is already a QT menu - the properties of Constellation
Object. You might want to look at the source - just figure what you need
to do to keep it open.

-- Cinaed

Eng. Luis Felipe Albarracin
Msc. Telematics / MBA
ITIL v3 Foundation
"Die Grenzen meiner Sprache bedeuten die Grenzen meiner Welt"

Attachment: Mod_Simple.grc
Description: Binary data

reply via email to

[Prev in Thread] Current Thread [Next in Thread]