User Manual

SFG-1000 Series User Manual

Block diagram

DDS synthesizer consists of Phase accumulator

(counter), lookout table data (ROM), Digital-to-analog

converter (DAC), and Low-pass filter (LPF).

Frequency

Control Word (K)

28bit

Phase

Accumulator

28bit

Table

ROM/RAM

Digital-Analog

Converter

Low-Pass

Filter

System Clock

(fs)

Output (fo)

28bit

12bit

The phase accumulator adds the frequency control word

K at every clock cycle fs. The accumulator output points

to a location in the Table ROM/RAM. The DAC

converts the digital data into an analog waveform. The

LPF filters out the clock frequency to provide a pure

waveform.