Answer:
The smallest angle is 0.196 rad or 11.25º , Â
102 signals
Explanation:
As the decoder sends a signal every change of intensity, 2 signals are sent per line, in total we have 2 * 16 = 32 signals / rev
The angle covered for each signal is
   Δθ = 1 2π / 32 = 0.196 rad
   Δθ = 0.196 rad (180º / π rad) = 11.25º
The smallest angle is 0.196 rad or 11.25º
Let's track the signals send to have 2 meters
Angular and linear variables are related.
   θ = S / r
   S = R θ
   S = 0.1  0.196
   S = 0.0196 m
   N = 1 2 / 0.0196 = 102.04 signals
  102 signals should be read
Change resolution to ΔS = 0.20 m
The angle for this distance is
  Δθ = ΔS / R
  Δθ = ΔS / R
  Δθ = 0.20 / 0.1
  Δθ = 2 rad
If we have one signal every 2 rad how many signals for 2Ï€ rad
  N = 2π 1/2 = π = 3.14
As each line sent signals 2 lines are needed only