100Mhz with Analog Discovery

[tdeball]

Hi,

I have a project where I am trying to create a 100Hhz sine or square wave to be used a clock input to a device. I have an Analog Discovery 2 and ADP3250. Both datasheets say they can generate waveforms at 125Mhz, but when I am in the Wavegen tab of Waveforms, I can only get it to go to 31.25Mhz for a sine or square wave.

Are these devices capable of of generating a 100Mhz sine or square wave? If so, how?

Thanks!

[zygot]

The short answer is no.

The -3 dB analog bandwidth for the AD3xxx Waveform Generator is 15 MHz. The DAC output bandwidth of the AD2 is about the same. If a digital waveform generator can create outputs samples at 125 MHz there wouldn't too many samples/waveform cycle for a 100 MHz sine wave would there? There are analog techniques for creating sine-like waveforms out of square waveforms but the AD2 and AD3xxx are not that kind of waveform generator instrument. On the other hand these instruments do allow you to create fairly complex waveforms of using a limited number of samples per output waveform cycle period.

If you were happy with a 100 MHz sinewave constructed out of 256 samples, then the DAC sample frequency would have to be 2.56 GHz and the -3 dB analog bandwidth would have to be considerably larger than 100 Mhz. For a decent quality square or triangle 100 MHz waveform an even larger analog bandwidth would be required.

I suspect that none of this is really much of a surprise to you if you think about it a bit. Edited January 15, 2023 by zygot

[JColvin]

Hi @tdeball,

@zygot is correct, neither of the devices are able to produce a 100 MHz square wave output.

Rather, all of their material is stated to say that the devices operate at 100 MSamples/second not Hertz (please let me know if you see something listed differently).

Thanks,
JColvin