Implement an alternative to SNR function

Folks,

I have x as following:

[x,Fs] = audioread(strcat(PathName,FileName));

And some noise in the form of alpha*v as below:

rng('default');
alpha=0.2;
v = randn(size(x));

I don't have Signal Processing toolbox to use snr() function. How can I find SNR as given in this equation?

Answer 1

[Walter Roberson]

hint:

sum(x.^2)

[Hasan Ghorbani]

Thansk. Am I right by using following code:

x_snr_db = 20 * log10( sum(x.^2) / sum((alpha * v).^2) );

[Walter Roberson]

Where did the 20 come from?