
Edited by gf1 at 2019217 18:53
... In th AWG mode, the waveform is clipping on the negative side as I increase the amplitude to near the 2.5V limit or if I set a negative offse...
I'm facing the same issue as well on my 2D72. I measure a supply voltage of +5V / 3.3V on the output amp (EL5166) of the AWG. According to the datasheet, the output of the EL5166 can swing to within 1V of either supply rail, so 2.5V is actually beyond this limit. Fixing this issue would IMO require a hardware change (i.e. increase the negative supply voltage of the amp).
The jitter of the AFG is pretty horrendous, specially with frequencies over 1MHz. Is that normal?
 Since the AWG's DAC is clocked at 250MSPS, the pulse width of both, the positive and negative pulse of the quare wave, can only be an integral multiples of 4ns. If the selected frequency does not grant this, then some of the pulses need to be streched or shortened in order that the generated frequency is correct on average.
 Additional (theoretical) limitations are imposed by the way how Direct Digital Synthesis (DDS) works. One of them are phase truncation errors, but there is also the limitation that a DDS generator can only generate frequencies wich are integral multiple of DAC_clock_freqency / dds_accumulator_size, where dds_accumulator_size is a power of 2 (I don't know what's the accumulator size on the hantek series 2000).
For instance, a 5MZh square wave would fulfill the condition (1), but the DDS can't generate exactly 5MHz, due to condition (2). But the closest frequency which can be generated by the DDS generator does no longer fulfill condition (1) and also suffers from phase truncation errors. So you are rather limited regarding the square wave frequencies which can be generated "exactly" without stretching/shortening some of the pulses (=> basically only power of 2 fractions of the DAC clock freqency).
If I try for instance 7.8125 MZh (= 250MZh / 32) on my 2D72, I get a nice square wave  but not for any arbitrary frequency.
Regarding DDS, see for instance https://www.analog.com/media/en/ ... utorials/MT085.pdf, or one of the many other DDS resources which can be found in the internet.
EDIT:
Square waves and pulses with very steep edges and/or small pulse widths are of course the worst case waveforms forms for DDS, when they should be reproduced at higher frequencies. Sine waves are not a problem in this regard, since they are already bandlimited to the sine wave frequency. But for other kind of waveforms, the resampling done by the DDS may eventually violate the Nyquist–Shannon sampling when generating signals with higher frequencies, and this implies that the signal cannot be reconstructed exactly from the sampled data.
A possible workaround you can do is to increase the rise time (and thus reduce the bandwidth) of the square wave manually, by approximating a square wave with a trapezia. If you generate, for instance, a trapezia on the Hantek 2000, with RiseDuty=FallDuty=0.08 and HighDuty=FallDuty=0.42 with 5MHZ, then you'll notice less jitter than with a 5MHz square wave  but at the cost of renouncing the steep rise time of a true square wave.
Regards,
gf1

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