TDS420A - Page 1
Forum section: electronics / testgear

author: gabrieleing
author_rank: Newbie
timestamp: December 14, 2014, 12:56:23 am
content: Hi to everybody, I am new of this blog, I need of an information about the Tektronix TDS420A, Is it possible to update it in order to include the FFT analysis?Thanks in advance!!!!!!

author: AlessandroAU
author_rank: Regular Contributor
timestamp: December 14, 2014, 02:25:15 pm
content: I have used this scope, it is painfully slow and has a small memory, I would not recommended it for FFT analysis, at all.That being said, it does have an FFT option in the math menu.

author: gabrieleing
author_rank: Newbie
timestamp: December 14, 2014, 03:14:29 pm
content: depend the option installed, my doesn't have this option.

author: Howardlong
author_rank: Super Contributor
timestamp: December 14, 2014, 03:16:49 pm
content: It's option 2F, I don't know if it can be added on with a tweak or otherwise, but I did see recently that certain features on some Tek scopes of the era can be added with field calibration software loaded onto an ISA DOS machine with the right ISA GPIB card.I have a fully loaded 460A, it works, but IMHO it's little more than an interesting aside, I find the UI a bit of a pig, both in its design and because it's so slow as Alessandro says. I don't use it for real work for many reasons, mainly due to its low sampling rate, it doesn't take much for it to start going into equivalent time sampling.Software-wise, it was a pretty well featured scope for its time though.

author: Mark_O
author_rank: Frequent Contributor
timestamp: December 16, 2014, 06:24:29 am
content: Quote from: Howardlong on December 14, 2014, 03:16:49 pmWow, we have pretty radically different opinions of this unit. I have a couple, and found them quite useful and usable... for their time. I still use one of them occasionally. The only real disappointment I can recall was discovering the (relatively) slow sample rate of 100MSa/s, coupled with the impressive 400 MHz BW. As you said, that meant it was often an ET sampler, and for one-shot acquisitions was basically a 40 MHz scope. Still, not terrible for many purposes.QuoteI'd agree with that.

author: TriodeTiger
author_rank: Regular Contributor
timestamp: December 16, 2014, 06:32:15 am
content: Quote from: gabrieleing on December 14, 2014, 12:56:23 amYeah, on my 460A I discovered conformal coating over my NVRAM so I decided I'd just use a floppy to plot FFT in MATLAB instead of buying a pricey cable adapter for dumping the EEPROM another way. If you have a virtual serial cable, that might be quicker actually to get FFTs in Python or whatnot rather than waiting for the slow scope to do it.

author: Howardlong
author_rank: Super Contributor
timestamp: December 16, 2014, 06:39:33 am
content: I just find that I am in a continuous battle with the UI. To this day, I still cannot figure out how to show dual trigger and timebase sweep simultaneously: I feel sure it must be possible! It has the zoom function, but that's not the same.If I want to do this on an old CRO like a 2465 or 465, it's simple. I am, as always, willing to be educated!

author: David Hess
author_rank: Super Contributor
timestamp: December 20, 2014, 07:49:55 am
content: Quote from: Howardlong on December 16, 2014, 06:39:33 amI am not sure what you mean by dual trigger. Do you mean dual timebase?Some old DSOs like the Tektronix 2440 series support a dual delayed timebase which duplicates the same function on the 2465, 2247A, and 7000 series but that is different. To get a dual timebase on a DSO, I use two separate instruments.

author: Howardlong
author_rank: Super Contributor
timestamp: December 20, 2014, 08:22:44 am
content: Thank you David, that was exactly what I was trying to achieve, dual timebase with delayed trigger, like the 2465 et al.There is zoom and delayed timebase, but I've not been able to figure out how to get a second timebase (and possibly sampling rate) simultaneously displayed. I guess it just doesn't do that.

author: David Hess
author_rank: Super Contributor
timestamp: December 23, 2014, 03:11:01 am
content: I actually should have said dual delta delayed timebase. I think the reason you will not find support for this on a modern DSO is that it is not needed. Its principle use was to measure delay accurately between signal features and DSOs can do this using automatic measurements or cursors.The only DSOs which I know of which support this are the Tektronix 2440 series.

author: maxxim
author_rank: Contributor
timestamp: January 11, 2020, 06:17:37 pm
content: Hi, what is the value of the tantalum capacitor on the underside power supply pcb (hybrid pin 13-19).Thanks