What is does a resolution of "11.8 bits" mean when looking at a digital signal?
ENOB (Effective number of bits) is defined as: 

\$ \text {ENOB} = \frac{SINAD - 10 \log_{10}(3/2)}{20 \log_{10}(2)} \$

SINAD is the signal to noise and distortion ratio (in dB) 

So, it's the resolution of an equivalent ideal ADC. Resolution in bits is \$\log_2(n)\$ where n is the total number of output codes, so an 11.8 bit ADC would have 3566 distinct output codes.