sdr.FLFSR.feedback_poly

property sdr.FLFSR.feedback_poly : Poly

The feedback polynomial $f (x)$ that defines the feedback arithmetic.

Notes¶

The feedback polynomial $f (x) = - c_{0} \cdot x^{n} - c_{1} \cdot x^{n - 1} - \dots - c_{n - 2} \cdot x^{2} - c_{n - 1} \cdot x + 1$ is the reciprocal of the characteristic polynomial $f (x) = x^{n} \cdot c (x^{- 1})$ .

Examples¶

In [1]: c = galois.primitive_poly(7, 4); c
Out[1]: Poly(x^4 + x^2 + 3x + 5, GF(7))

In [2]: lfsr = sdr.FLFSR(c); lfsr
Out[2]: <Fibonacci LFSR: c(x) = x^4 + x^2 + 3x + 5 over GF(7)>

In [3]: lfsr.feedback_poly
Out[3]: Poly(5x^4 + 3x^3 + x^2 + 1, GF(7))

In [4]: lfsr.feedback_poly == lfsr.characteristic_poly.reverse()
Out[4]: True