Re: [Discuss-gnuradio] Question regarding correlating output and IQ samples in a reciever

[abhinav narain]

Hi Marcus, 

 

I am simply doing OOK.

 

Generally, is only really a useful measure if you either have

1. a constant power modulation (e.g. PSK), or
   
2. whiten your over-the-air bits sufficiently (using coding), so that for (stochastically speaking almost any) data sequence, the signal power is the same.

Usually, even when you have 1., you do 2..

so the above formula is what I am using currently over the whole message run, and for similar amount of time when no message was transmitted to get S+N/N .

I have looked through Gnuradio docs and doesn't seem to appeal that there is any of the four would work.

Sorry, I don't understand what you're referring to; could you explain? 

Apologies for being inarticulate.

I don't think OOK is constant power modulation, but I suppose S+N/N should still apply on it.

I am using the  formula by calculating the following:n

a) Use the iq samples of the data part of the transmission to get S+N 

b) Measure noise for same number of samples (when the transmission is not going on) to calculate expected value of N

Divide the two and take the log to get the SNR value for the scheme.

Is that correct ?

Thanks,

Abhinav