Hello Charles,
There is not currently a way to display this number. To clarify as well, MER(dB) == SNR(dB) ?
You can find an equation for the EVM(%) -> SNR(dB) conversion here.
https://www.keysight.com/main/editorial.jspx?ckey=847674&id=847674&nid=-11143.0.00&lc=eng&cc=UG
I can look into adding this for a future release of Spike. I look forward to your response.
Regards,
Andrew