Phase Shift Keying (PSK) is a digital angle modulation format wherein digital binary or M-ary symbols are mapped onto abrupt, discrete phase shifts of a constant-amplitude sinusoidal radio carrier wave. In Binary Phase Shift Keying (BPSK), logic 1 and logic 0 modulate the carrier phase between 0 and 180 degrees (π radians), achieving optimal bit error rate performance under additive white Gaussian noise conditions.