What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital-to-analog converter, and a low-pass anti-alias filter?

Direct Digital Synthesis (DDS) is a method of producing an analog waveform, usually a sine wave, by generating a time-varying signal in digital form and then performing a digital-to-analog conversion. The key components of a DDS are a phase accumulator (which tracks the phase of the wave), a lookup table (which converts phase values into amplitude values), a digital-to-analog converter (DAC), and a low-pass anti-alias filter to smooth the final analog output. Phase-locked loop (PLL) synthesizers, on the other hand, rely on analog-driven components like a voltage-controlled oscillator (VCO), phase detector, and frequency divider. Any time you see a combination of a lookup table and a digital-to-analog converter generating a frequency, it is a direct digital synthesizer.