Hi Peter;
I am curious to know in what paper/book/report/manual you found the shown SNR definition.
I’m asking because, from an application perspective it makes sense so subtract the NESZ from sigma naught (in the numerator) however the ‘traditional electrical engineering’ definition of SNR does not do so, i.e. it is simply the ratio of sigma naught over the NESZ (in other words the signal is considered to be noise free). I saw SNR defined in the way you show in a recent paper by J.M. Lopez-Sanchez et al., RS of Env, no.192, 2017, pp.30-44 but they didn’t include a reference and I’m thinking there must be one that predates their paper, ideally, in some respected handbook.
Thank you