Vartech's function generator range runs from a 6 MHz entry-level DDS unit to an 80 MHz fully programmable dual-channel arbitrary waveform generator, five models on the same basic DDS (Direct Digital Synthesis) architecture at increasing frequency, sample rate, and control sophistication. Specifying the right one is mostly a question of how much bandwidth your stimulus signal needs and how much automation your test setup requires.
The Frequency Ladder: 6 MHz to 80 MHz
The range steps up in a clear progression - SGD-6M (6 MHz) → SGDA-15M (15 MHz) → SGDA-30M (30 MHz) → SGDA-60M (60 MHz) → SGDA-80M (80 MHz) - all dual-channel DDS generators. As with any signal source, specify frequency based on the actual stimulus signal you need to generate, not the frequency of the circuit under test - if you're characterising a circuit's response across a range of frequencies (a filter's cutoff, for instance), the generator needs to comfortably sweep past the highest frequency of interest.
Sample Rate and Waveform Fidelity
Sample rate determines how cleanly the generator can reproduce a waveform, particularly for arbitrary (non-standard) shapes. The SGD-6M offers 200 MSa/s, the SGDA-15M and SGDA-30M step up to 266 MSa/s, the SGDA-60M reaches 275 MSa/s, and the SGDA-80M tops the range at 300 MSa/s. Higher sample rate matters most when generating arbitrary waveforms or complex modulated signals - for simple sine/square/triangle output at moderate frequencies, the entry-level models are entirely adequate.
Arbitrary Waveform Capability
The SGDA-15M and SGDA-30M offer 60 built-in arbitrary waveforms on a 2.4-inch TFT display - useful for simulating non-standard signal shapes without programming a custom waveform. The SGDA-60M and SGDA-80M go further, supporting full custom arbitrary waveform generation with larger colour displays (2.8-inch and 3.5-inch TFT respectively) and a complete modulation suite, positioning them for genuine signal-simulation work rather than just basic sine/square/triangle output.
Built-in frequency counter
Automated Test - The SGDA-80M
The range-topping SGDA-80M is built for automated and programmable test work - full modulation suite, USB interface, and dual-channel 300 MSa/s output designed for integration into an automated test sequence rather than purely manual bench use. If your application is a one-off bench stimulus signal, the mid-range models cover it; if you're building a repeatable, PC-controlled test setup, the SGDA-80M's programmability is the deciding factor.
Quick Reference by Use Case
- Basic bench signal generation, education: SGD-6M, 6 MHz entry-level DDS.
- General electronics bench, moderate frequency work: SGDA-15M or SGDA-30M.
- Higher-frequency work, richer arbitrary waveforms: SGDA-60M.
- Automated / programmable test sequences, high-frequency stimulus: SGDA-80M.
CIE Instruments is an authorised distributor for the full Vartech function generator range. See our general guide on how to choose a function generator for the underlying specifications, or contact us for a model recommendation matched to your bench.