Phase-to-amplitude Converter
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 2M contiguous samples of the desired output waveform which typically is a sinusoid. Oftentimes though, various tricks are employed to reduce the amount of memory required. This include various trigonometric expansions, trigonometric approximations and methods which take advantage of the quadrature symmetry exhibited by sinusoids. Alternatively, the PAC may consist of random access memory which can be filled as desired to create an arbitrary waveform generator.
Read more about this topic: Numerically Controlled Oscillator