GW Instek SFG-2120 20MHz DDS Function Generator with Sweep/Mod./Counter

The SFG-2120 Series are packed with features and performance, making them some of the most cost effective signal generators GWInstek has produced to date. Like the SFG-2000 series, the SFG-2120 is based on Direct Digital Synthesized (DDS) technology with a custom embedded FPGA. The SFG-2120 operates at 20MHz and includes AM/FM modulation, Sweep functionality and an external counter, making it an extremely versatile instrument for signal generation.

The SFG-2120 generates signals by continuously delivering a series of sampling values from a sine waveform table (stored in RAM) to DAC (Digital to Analog Converter) for waveform construction. With a low pass filter circuit to filter out the harmonics of the DAC output and smooth the signal, the SFG-2120 is able to provide a stable output with very low waveform distortion. This is very different from the way a conventional FG generates a signal. Since a conventional FG needs to obtain its signal by switching current sources between positive and negative directions all the time, the "Ringing" distortion occurs at the peak of the signal waveform where the switching is activated. This distortion is especially serious when the output amplitude is low. For the SFG-2120 DDS Function Generator, however, the waveform distortion remains low even when the output amplitude is at only 2mVpp.