Phase lock loop functions

Classes
class	SPUC::bool_nco
	NCO with single bit output. More...
class	SPUC::loop_filter< Numeric >
	Loop Filter for use in PLL circuits. More...
class	SPUC::nco
	NCO with 32 bit accumulator. More...
class	SPUC::vco
	VCO similar to NCO but uses floating point. More...

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