0

I have implemented this:

image

Constellation plot of receiver side is same as that of transmitter but it disappears for some moment and is not continuous, It flickers and keeps on moving around and for a very short moment show a garbage plot also.

How to resolve that to get a correct continuous plot?

Marcus Müller
  • 34,677
  • 4
  • 53
  • 94
Khan
  • 23
  • 1
  • 7

1 Answers1

0

Never use a "Throttle" block in a hardware flow graph.

What it does is just slow down the processing speed "about roughly" to the requested rate on average. That will sooner or later lead to your computer not fetching the samples from your hardware source quick enough, and you run into overflows.

That is probably the moment when you see "garbage" plots.

Generally, 20 MS/s is a lot, and usually, hard drives aren't reliably fast enough at writing away that data. Also disable the file sink if the problem persists.

it disappears for some moment and is not continuous, It flickers and keeps on moving around

Congratulations! You discovered the wireless channel. That's what happens. Consult your wireless communications basics knowledge for more on that; this is not a programming problem :)

Marcus Müller
  • 34,677
  • 4
  • 53
  • 94
  • I am very much able to resolve my problem as per your guidance. What i am actually implementing is to modulate and transmit, receive and demodulate the data.And i receive correctly as long as i use packet decoder and encoder. Is there any way to tackle that? – Khan Jun 08 '19 at 20:04
  • yes, as I've said multiple times: you can't use the packet decoder and encoder. It's sporadically broken. you can use the framework with the payload/header demux blocks that you can find in the gr-digital examples. – Marcus Müller Jun 08 '19 at 21:54
  • I did a search on it and found out its use in flow graph: It was used with OFDM Demod/Mod blocks. But I want to use DPSK Mod and DPSK Demod blocks only, with that simple flow graph as attached. Could you please guide? – Khan Jun 10 '19 at 03:29