The phase-amplitude converter creates the sample-___domain waveform from the truncated phase output word received from the PA. The PAC can be a simple [[read only memory]] containing 2<sup>M</sup> contiguous samples of the desired output waveform which typically is a sinusoid. Often though, various tricks are employed to reduce the amount of memory required. This include various trigonometric expansions,<ref>{{ Citationcite patent | inventor-last = Miller | inventor-first = B. M. | issue-date = October 14, 2008 | title = Numerically controlled oscillator and method of operation | country-code = US | patent-number = 7437391 }}</ref> trigonometric approximations<ref name="Grzeg">{{ cite web | first1 = G. | last1 = Popek | first2 = M. | last2 = Kampik | title = Low-Spur Numerically Controlled Oscillator Using Taylor Series Approximation | url = http://mechatronika.polsl.pl/owd/pdf2009/030.pdf | date = October 2009 | work = XI International PhD Workshop OWD 2009 | publisher = Silesian University of Technology | ___location = Gliwice, Poland }}</ref> and methods which take advantage of the quadrature symmetry exhibited by sinusoids.<ref>{{ Citationcite patent | inventor1-last = McCallister | inventor1-first = R. D. | inventor2-last = Shearer | inventor2-first = D. | publication-date = 12/04/1984 | title = Numerically controlled oscillator using quadrant replication and function decomposition | country-code = US | patent-number = 4486846 }}</ref> Alternatively, the PAC may consist of [[random access memory]] which can be filled as desired to create an [[arbitrary waveform generator]].
