Furuno FELCOM 12 Service Manual page 40

BPSK Modulation
BPSK is a kind of phase modulation using a digital signal. Depending on carrier phase
difference, BPSK is expressed as 0 or 1. Data signal "0" is not phase shifted; data
signal "1" is phase shifted 180 degrees.
BPSK modulator
Carrier
Frame synchronization
Detects a unique word.
De-permuting
Demodulated signal is de-permuted and input to the interleave matrix.
De-interleaving
Reassembles the message in the interleave matrix.
Viterbi Decoding
Decodes the viterbi-encoded signal.
De-scrambling
Scrambled signal is decorded.
BPSK modulated signal
Digital signal
Figure 2-12 BPSK Modulation
H L L
Phase no phase
change change
by 180°
2-9
H L
Phase Phase
change change
by 180° by 180°