GW Instek SFG-1000 Series - Manual (Page 10)

SFG-1000 Series User Manual
10
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
Register
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.