Algorithm 1 Pseudocode for Signal Modulation
1: initialize n, ref[n], measured[n], $m\leftarrow 0$, J, $J_{\mathrm{thresh}}$
2: $i\leftarrow$$n-1$
3: while $i>0$ do
4:  measured[i] ← measured[$i-1$]	▹ Shift the data array to the right by one
5:  $i\leftarrow i-1$
6: measured[0] ← current measured value (i.e., 0 or 1)
7: $j\leftarrow 0$
8: while $j<n$ do
9:  if measured[j] == ref[j] then	▹ Compare the $j^{th}$ bit
10:    $m\leftarrow m+1$
11:  $j\leftarrow j+1$
12: $J\leftarrow m/n$
13: if $J\ge J_{\mathrm{thresh}}$ then	▹ Signal matching case
14:  retrieve x and y position	▹ Obtain x and y position information