Extra exam question E7H09

WhyA direct digital synthesizer is the frequency synthesizer circuit that uses a phase accumulator, lookup table, digital-to-analog converter, and a low-pass anti-alias filter. A direct digital synthesizer builds its output using a phase accumulator (tracking the desired output phase step by step), a lookup table (converting that phase into an amplitude value), a digital-to-analog converter (turning those amplitude values into an analog waveform), and a low-pass anti-alias filter (smoothing the DAC's stepped output), answer A. Hybrid synthesizers, phase-locked loop synthesizers, and "direct conversion synthesizers" (not a standard synthesizer category) don't use this specific phase-accumulator-and-lookup-table architecture.