Re: [Discuss-gnuradio] gr-ieee802-11 wifi signal bitrate

[Bastian Bloessl]

Hi Thomas,

> On 7. May 2017, at 09:21, Thom L <address@hidden> wrote:
> I added a time block sink and watched the signal in 6M mode (sampling rate is 
> 20M) but I can not interpret the result (cf attachment). Well I do not have 
> to look at the right place or the right way ..

I’m not sure what you are trying to visualise, but the equalizer outputs the 
data subcarriers. In the picture it shows BPSK, where the constellation points 
are around (-1, 0) and (1,0).
The time domain plot interprets the subcarriers as time series and visualises 
real and imaginary parts in a line plot. The red line is the complex component 
(which is around 0), while the blue line shows the real part (which jumps 
between 1 and -1).

> In fact I can not quite understand the graph in the time domain which is by 
> default in the module gr-ieee811 (magnitude)

IIRC, it shows the autocorrelation of the signal. If you add a trigger to the 
default plot (level ~0.56) you should see the characteristic plateau of the 
short training sequence at the beginning of frames (this is used for frame 
detection).

Best,
Bastian