Hello, I would like to write some code to calculate the SNR of a signal;

in my case this signal is a packet radio AX25 1200 baud packet burst

received thru TV RX and usrp.

First you need to define SNR. If you measure the noise power of the

background within the passband when there is no signal, and then

measure the power of the signal+noise while receiving, you can

calculate an estimate.

Or, you can do coherent demod of the signal, and then regenerate a

perfect signal at an amplitude that best matches the received data.

Then you can subtract that and look at the residuals, and calculate

power of the reconstructed signal and the residuals. The residuals

will have not only noise and receiver distortion, but also components

due to amplitude variations over the estimation period.

This is probably much easier if you don’t try to get accurate values

at low SNR. But it’s down low that it’s a more interesting problem,

at least to me.

–

Greg T. [email protected]