
294 CHAPTER 17. PROJECT 8: BPSK DIGITAL RECEIVERS
3. (Line 7): Applies a scale factor to the signal and accounts for the group delay of the
Hilbert transforming FIR filter prior to the PLL.
4. (Lines 10–12): Update the buffered values of x for the next ISR call.
5. (Line 14): Applies a scale factor to the signal prior to the PLL.
6. (Lines 17–30): Implement the PLL.
7. (Lines 33–43): Implement the FIR-based matched filter.
8. (Line 46): Implements the FIR-based second difference filter which is a very close
approximation to differentiation.
9. (Line 49): Turns the codec’s channel synchronization pulse off.
10. (Lines 50–80): Implement the ML timing recovery ...