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

From: Cinaed Simson
Subject: Re: [Discuss-gnuradio] BER Example - With QT Gui Chooser for Different Modulations Issue
Date: Fri, 25 Jan 2019 12:20:22 -0800
User-agent: Mozilla/5.0 (X11; Linux i686; rv:60.0) Gecko/20100101 Thunderbird/60.4.0

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

Attachment: my-ber-test.grc
Description: Text Data

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