How many signal levels are required when the bandwidth is 2MHz and to noise ratio 8 dB?

Step 1: Calculate the number of quantization levels required for the given signal-to-noise ratio (SNR) and bandwidth.

$$L=1+ \log_2(1+\text{SNR})$$

$$L=1+\log_2(1+8)$$

$$L=4.3219=4 \ bits$$

Therefore, the number of signal levels required is 4.