How do I convert a Eb/No from a dB value to a linear value
For a power value, the decibel value is given by \$10\log_{10}{\text{SNR}}\$. To obtain the SNR from the dB value, take the inverse of this formula: \$\text{SNR} = 10^{\text{SNR}_{dB}/10}\$. In your example, 2 dB SNR corresponds to an SNR of approximately 1.58.

Note that this gives SNR power ratio. If you want an amplitude ratio (assuming there's a square-law relationship, as with electronic signals in many cases), take the square root of the power SNR.