Blog - All Comments

RE: Measuring Pmod Switching Speed with a High-Bandwidth Oscilloscope

michaelkellett — Fri, 31 Oct 2025 09:21:14 GMT

I'm sure I've seen an article very like this from some time ago. Then, as now, the experimental technique was quite inadequate and the information provided insufficient to determine the sources of error.

It is not possible to accurately measure 100MHz+ signals with huge loops of earth wire to the scope probes.

The article does not state what probes were used.

The settings of the 5490 were not discussed.

There is an error in your post:

At 60 MHz, the signals still transitioned cleanly, but the waveform edges showed slower slew rates

The slew rate is about the same at 10MHz and 60MHz but the effect on the waveform shape is 6x more significant at 60MHz - the original article explains this properly.

There is a lot of information on the web about probing techniques for high speed signals. Shabaz has posted some low cost ideas on E14.

RE: New Product Announcement: Analog Discovery Studio Max

Gough Lui — Fri, 20 Jun 2025 12:15:22 GMT

Interesting. Looks like this is a "reborn" NI ELVIS ...

RE: New Product Announcement: Analog Discovery Studio Max

dougw — Tue, 17 Jun 2025 23:02:38 GMT

I has taken me decades to collect this level of functionality, but this is well integrated into one system, and the comprehensive software deserves a special mention.. What an awesome head start for anyone with an electronics passion.

RE: New Product Announcement: Analog Discovery Studio Max

DAB — Tue, 17 Jun 2025 20:34:40 GMT

Nice unit.

It would be good for students and builders.

RE: New Product Announcement: Analog Discovery Studio Max

battlecoder — Tue, 17 Jun 2025 20:30:52 GMT

Nice!
I'm a big fan of the Analog Discovery family of devices (have the AD2 and several of its modules/adapters) and I've always liked the concept of an integrated breadboard plus instrumentation and power supply combo that the ADS embodies. I'm sure it would help reduce the nest of flying wires and probes that are all too common when prototyping something. Plus I assume it would make things easy to move around if I need to set the whole project aside for a bit, or if I need to take it somewhere else.
I particularly love the upgraded supply specs and options.Not that the original Analog Discovery Studio platform was lacking, but this gives room for more experiments around audio amplifiers or motor controllers.

Note: Maybe it's a regional thing but the links to the store are not working for me.

RE: Exploring FPGA Pin Performance with Digilent's New High-Bandwidth Oscilloscopes

jc2048 — Wed, 16 Apr 2025 12:38:30 GMT

Thanks for the blog.

This is a 72MHz LVCMOS output from the PMOD connector on an iCEstick, as viewed on an old Tek 2000 series 200MHz scope using a passive x10 probe and probing as well as I can directly on the connector with a springy-clip ground (I've done what you did, and generated a clock with the PLL and pushed it out of an IO pin).

Although the very fast edges without termination make for a somewhat messy waveform, even with just the short length of track to the connector, I don't think you'd complain that the chip was tardy in leaping between the rails. The risetime that you see (~2ns) is that listed for the scope, not the FPGA pin driver.

You've got a faster FPGA and a faster scope, so why are you seeing such a slewrate limitation on all your waveforms?

You've probably considered these, but worth asking. Are you using the probes x1 (lower bandwidth than x10)? Do you have a bandwidth filter enabled on the scope? Have you set the FPGA pin slewrate to slow (that might be the default in the design software)? Are you using the lowest drive current on the pin?

RE: Exploring FPGA Pin Performance with Digilent's New High-Bandwidth Oscilloscopes

michaelkellett — Mon, 14 Apr 2025 17:01:01 GMT

Looking at your test rig I think you are measuring the frequency response of the inductive loop formed by your ground leads and the capacitance of the probe, suitably modified by any imperfections in the probe and its cable.

What probes were you using ?

Most probes come with little spring clips to attach to BNC sockets and the like - you will be impressed by how much the waveforms change when you use them !

(The are not the ideal solution for the ARTY board but much better than the long earth leads.)

RE: Exploring FPGA Pin Performance with Digilent's New High-Bandwidth Oscilloscopes

dougw — Mon, 14 Apr 2025 16:12:41 GMT

1.5 GS/s & 2 GS/s .... pretty useful

RE: Exploring the World of Thermocouples: Overcoming Measurement Challenges with Raspberry Pi-based MCC 134 DAQ HAT

DAB — Tue, 13 Feb 2024 20:02:04 GMT

Interesting board.

Do you have any graphs showing how stable the unit is in 24 bits.

Unless you have a very quiet environment, you usually have a lot of noise so your accuracy suffers when you have to filter the data.

RE: Dual Device Mode for Analog Discovery 3

DAB — Tue, 26 Sep 2023 19:04:25 GMT

Good idea with cascading the devices.

RE: Analog Discovery 3 - What's different?

genebren — Wed, 09 Aug 2023 21:59:47 GMT

A good thing getting better! Now that is the way things are supposed to work!

RE: Analog Discovery 3 - What's different?

DAB — Wed, 09 Aug 2023 20:39:58 GMT

Definitely an interesting device.

RE: Analog Discovery 3 - What's different?

dougw — Wed, 09 Aug 2023 15:45:58 GMT

Nice upgrade.

RE: DPS3340 Discovery USB Programmable Power Supply

colporteur — Mon, 17 Apr 2023 21:04:56 GMT

I thought it might be a replacement for my project board PS but at $750 US that is some serious coin for such a device. I looked through the specs and found nothing that suggests I would purchase the unit for this reason. Can anyone provide some insight? What am I missing?

RE: Digilent launches The Analog Discovery Pro model ADP3450

michaelkellett — Fri, 09 Apr 2021 09:13:23 GMT

Thanks for the heads up. It's interesting , but .............................

4 channel scope 55 MHz for $1300 - very poorly specified (I don't mean bad figures, just an absence of figures )

For example I can't tell how many ranges it has - looks like 2.

Update rate not specified.

Compare with the specs for Tek, Keysight,R&S, Rigol and Pico - all of them provide this information and much more.

(Pico 5442D MSO is flex resolution £1365, 60MHz, all the others offer scopes with screens in this price range)

The Digilent price does not include probes.

It does have some interesting features - like the network analyser but the spec says so little about performance that I can't tell if it would be much use.

(Pico offer free software add on for bode plotting (on scopes with AWG) - other scopes have similar offerings)

If NI/Digilent want to break into the serious scope market they'll need to raise their game.

A RoadTest would be good idea - it would answer some of my questions.