DPSK demodulator circuit

[promach]

In A DPSK demodulator for biomedical application , how to obtain the two MSB waveform signals in orange and green colors from Pulse+ and Pulse- signals ?

[Foxxz]

It looks like for Pulse- the digital DPSK used as a reset line is an active low which resets a counter. When pulse- sees two pulses the counter outputs a pulse for approximately 1 clock cycle.

Pulse+ is the save except that the digital DPSK used as a reset is an active high.

[promach]

But it still does not make sense to me why there is only a single green MSB pulse generated ?

[Foxxz]

Because near the middle of the logic waveform is the only time when there are two green pulses while digital DPSK is high. I'm assuming while the digitial DPSK is held low the counter value stays at 0 and its not an edge detect. Unfortunately the waveform by itself isn't enough to determine this.

[promach]

Why would the orange Pulse+ signal needs active-low Reset signal ?

Why would the green Pulse- signal needs active-high Reset signal ?

[promach]

I think the two RESET signals into the 2-bit counter module might be wrong, they should be swapped with each other.

Besides, this circuit is only for demodulating DBPSK if I am not wrong ?

What about DQPSK and 8-DPSK ?

[SiliconWizard]

It looks right to me. Indeed the author here has assumed the two counters had a low-level active reset, which should IMO have been noted with a circle at the reset inputs or something.

If you count pulses between reset events, the MSB signals look right. Or I missed something.