Re: BPSK tutorial

Javier,

It can be very confusing! First, you need to work through every step of
the https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation
(QPSK) tutorial. It uses 2 bit symbols and 4 samples per symbol.

The BPSK tutorial uses 1 bit symbols and 4 samples per symbol. The
difference between QPSK and BPSK is the number of bits per symbol. In
both cases, the Constellation Modulator block uses all 8 input bits.
Note that the Constellation Object is different between QPSK and BPSK.

Then you need to build a new flowgraph for the
https://wiki.gnuradio.org/index.php/Simulation_example:_BPSK_Demodulation#Decoding

As you can see in the BPSK stage6 flowgraph, the CMA Equalizer is
optional under your conditions. I left it out of the BPSK to simplify
the flowgraph.

P.S. Please Cc discuss-gnuradio@gnu.org in your responses so that it is
included in the discussion thread.
---
Barry Duggan KV4FV
https://github.com/duggabe

On 8/27/20 7:56 AM, Javier Acevedo wrote:
> Dear Barry,
>
> Currently I am implementing a BPSK transceiver using the USRP N310,
> which has a sample rate of 125MS/s. Nevertheless, I have some doubts
> about the parameters which I have to set in GNU Radio in order to have a
> stable transceiver. For example, in your simulation you set the input
> using a random source, which produces random numbers from 0 to 255. I
> know that GNU Radio splits each input byte into 4 samples of 2 bits.
> Then, you are setting as input values from 0 to 3 -  00, 01, 10, 11 -.
> How does GNU Radio manage this since for BPSK you can assign each input
> value to only two constellation points
>
> In my real implementation I am using 0 only as input value because I
> want to prove that the transceiver works using only one constellation.
> Unfortunately, the following are the results that I have: please refer
> to the following link
> https://stackoverflow.com/questions/63603899/psk-modulation-in-gnu-radio-in-usrp-n310
>
> I would be immensely grateful if you could help me to clarify the
> questions that I formulate in OpenStackFlow.
>
> Best regards
> Javier Acevedo
>
> Am Do., 27. Aug. 2020 um 02:59 Uhr schrieb Barry Duggan
> <barry@dcsmail.net <mailto:barry@dcsmail.net>>:
>
> For those of you who have been asking questions about BPSK, I have
> created
> https://wiki.gnuradio.org/index.php/Simulation_example:_BPSK_Demodulation,
>
> which is a follow-on to the QPSK tutorial. Questions and comments are
> welcome!
>
> ---
> Barry Duggan KV4FV
> https://github.com/duggabe
>