Narrowband signal from the middle branch of correlators ON-TIME (fig. 3) goes to BPSK demodulator (fig. 5). Signal is amplified by 6MHz amplifier with T1 and is multiplied x2 to 12MHz by multiplier with T2. Multiplied signal has constant phase, but its envelope is deformed, his amplitude has fadings. Signal 12MHz is used to synchronize 12MHz generator made of T3, T4. Sinus 12MHz from this generator is amplified by T5. Amplified signal 12MHz goes to divider by 2 with trigger made of T6, T7. After amplifier and limiter with T8, T9 we have 6MHz square signal with constant phase which is used as pattern signal. Incoming BPSK signal amplified by T1 is additional amplified and limited by T10, T11. This signal is sumed with pattern 6MHz signal on R 10k. When their phases are the same, amplitude on R 10k increases. Wheh phases of both 6MHz signals are different, amplitude on R 10k decreases. After amplitude detector with T12 we have "1" or "0" depend phase of BPSK signal. This is digital audio signal equivalent to digital audio signal in transmitter. The output of BPSK demodulator does not recover original data polarity. We receive stream of bits identical or inverted compare to original digitalized voice stream in transmitter. In long time transmission, the polarity of digital signal can change a few times, because of fadings or disturbations of work of BPSK demodulator. Because as a digital to analog (D/A) converter we use integrator and low-pass filter, change of polarity of digital signal from BPSK demodulator causes only change phase of audio output signal. We can not hear it. It is why the polarity recover is no needed in receiver. Analog audio signal from R 4k7 goes to amplifier (fig. 6).
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