The Siglent SDG1000 series of Function/Arbitrary Waveform Generators are a new addition to the Circuit Specialists line of test equipment. These waveform generators are low cost, feature rich, Direct Digital Synthesis (DDS) function generators, that can provide two distinct signal outputs of either sine, square, ramp, pulse, noise, or an arbitrary waveform. Several models are available with output frequency ranging from 1 uHz (0.000001 Hz) up to 50 MHz. The units also feature modulation capability of AM, FM, PM, ASK, FSK, and PWM, as well as sweep and burst modes of operation. The output amplitude can be varied from 4 mV p.p. to 20 V p.p. into a high impedance load (2 mV to 10 V p.p. into 50 ohm load). Two different models are available from Circuit Specialists, the SDG1025 and the SDG1050. The SDG1050 model was chosen for this evaluation since it is capable of the highest frequency operation (50 MHz).
The highest frequency output is only available for the sine wave signal and the other waveforms are available at lower frequency values. The square wave maximum frequency is 25 MHz, the pulse waveform is 10 MHz, the ramp waveform is 300 KHz, and the arbitrary waveform is 5 MHz. Since the unit has two distinct output channels, each may be set to different frequencies, amplitudes, phase value, and waveform type. The phase angle between channels 1 and 2 can be adjusted in 0.1 degree increments all the way up to 360 degrees. The spectrum of the 50 MHz sine wave signal was viewed on a spectrum analyzer and found to be quite good for this type of instrument. Noise and harmonics were at
least 40 dB below the fundamental across the entire frequency range, which is quite impressive for a unit in this price range.
We next looked at the other waveforms and experimented with the additional capabilities of the unit such as duty cycle and symmetry of the square wave and ramp waveforms. The duty cycle of the waveform can be varied over a wide range of 20% to 80% up to 10 MHz and from 40% to 60% from 10MHz to 25 MHz. In Pulse mode of operation, the duty cycle may be adjusted from 8% to 92% for frequencies up to 5 MHz and from 0.1% to 99.9% for lower frequencies. A nice feature of this unit is the graphical display of the waveform on the units’ LCD screen. This provides a quick visual confirmation that the waveform being generated is what is desired. The modulation capabilities of the unit are quite
extensive and all functioned within the published specifications.
The Arbitrary waveform function was an area where this unit really shined. In addition to 48 pre-programmed special waveforms, ten additional user defined arbitrary waveforms may be stored in the units internal memory. An included computer interface program can be used to create any arbitrary waveform desired up to a maximum of 16 K data points in length. The waveform can then be stored in the units memory for future use.
The Siglent SDG1000 series of arbitrary waveform generators were found to be easy to use and have a built in Help menu to aid in the operation of the unit. The unit performed at or better than the published specifications through all of the available functions. Two units are currently available from Circuit Specialists, the SDG1025 and the SDG1050. The only difference in these two units is the maximum frequency range available.