Figure 3: Demodulation of BPSK signal.

(a) Pulse sequence. BPSK signal at 10.503 GHz with an amplitude of −125 dBm is generated by mixing the 10.553 GHz signal and 50 MHz intermediate frequency (IF) signal (blue curve). Phase of the IF signal is digitally modulated by π (corresponding to bit ‘0’ and bit ‘1’) every 500 ns and the pulsed pump (green curve) is synchronously applied. The magenta curve represents the expected output of the PPLO. (b) Examples of the demodulated signal. Twenty individual time traces are superposed.