Recent Posts

1

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by shapirus on Today at 04:09:40 pm »

We should probably continue this discussion in the TinySA thread, and report the bug to them as well. I'll try recreating it also when I have some time.

Makes sense.
Moved it here: https://www.eevblog.com/forum/testgear/tinysa-ultra-launched/msg5470555/#msg5470555

2

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by Mechatrommer on Today at 04:09:13 pm »

Riddle me this:
Signal theory also says there's only one curve that fits a set of sampled points in a bandwidth limited signal.
The "AM" signal fits perfectly so how can we say it's possible to reconstruct the original sine wave? It contradicts theory.

the possibility is i already mentioned...
1) oscilloscope is not properly BW limited, so Sinc filter is unable to reconstruct perfectly, instead of nice sine, it creates AM sine.
2) the filter probably assumes (algorithm used is for) "uniform sampling distance" where in reality is not.
https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem

maybe we can look the same test made by shapirus on SDS800X if scope can produce the same AM shaped signal very near to (but not reaching) Sr / 2. if SDS800X is properly BW limited and Sinc filter/interpolation is implemented correctly i suspect it will not create such AM shape, it should be nice 142MHz sine (constant amplitude on each cycle) unlike the picture you linked earlier (on Rigol DHO900) if sampled at slightly higher than 284MSps (such as 312.5MSps). ymmv.

3

Test Equipment / Re: TinySA Ultra launched

« Last post by shapirus on Today at 04:09:09 pm »

Moving the discussion concerning the output frequency glitches in the signal generator mode from another topic to here.

Someone please check if it reproduces with your TinySA Ultra to see if it's not only my unit that has these glitches.

Latest firmware update was 5 days ago on the TinySA Ultra. I wonder if they fixed that bug. There's been significant updates apparently since the version I had. I was using 1.4-120, now they're at 1.4-159.

Nope, same exact thing with 1.4-159.

Here's a demonstration with increased persistence (to see the glitches) and the lowest memory length for the max waveform update rate.

First, there's a 20 sec-long frequency sweep from 20 MHz to 120 MHz, then (00:30) frequency is changed manually in +100 kHz steps and finally (01:25) amplitude is changed manually.

As we can see, on any change in frequency or amplitude it has a brief period during which it outputs all sorts of crap. Frequency sweep output is the easiest way of catching it.

It's not the scope: it displays frequency sweeps from a different generator just fine, nice and clean.

4

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by mendip_discovery on Today at 04:05:52 pm »

l

You must have missed something, since they started out as a spam machine on day one. They used to do really sleazy things like harvest email addresses of professional people, and cross send invites to join like sending you "Your buddy Joe Blogs in on LinkedIn, and has invited you to join" while sending Joe Blogs the same invite claiming you were on LinkedIn.

That is how 90% of the internet worked back then. Facebook was no better. Remember a few years back everyone was sharing the next PayPal thing.

5

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by schmitt trigger on Today at 04:03:42 pm »

I initially thought of it as a Facebook for work related stuff. So you could make use of the contacts you have at work and not have them see the crazy stuff you get up to at the weekend.

I avoid it mostly as it wants to be a job advertising website and is infested with agencies trying to sell me a job that I left years ago.

Exactly my perception.
I did get a couple of job interviews about 15 years ago. But nowadays it is more of a nuisance.
I allowed my password to expire and never renewed it.

6

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by KungFuJosh on Today at 04:03:36 pm »

Latest firmware update was 5 days ago on the TinySA Ultra. I wonder if they fixed that bug. There's been significant updates apparently since the version I had. I was using 1.4-120, now they're at 1.4-159.

We should probably continue this discussion in the TinySA thread, and report the bug to them as well. I'll try recreating it also when I have some time.

7

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by coppice on Today at 04:00:26 pm »

I joined some years ago, dumped it when they started to get a reputation for spam and worthless recommendations.

You must have missed something, since they started out as a spam machine on day one. They used to do really sleazy things like harvest email addresses of professional people, and cross send invites to join like sending you "Your buddy Joe Blogs in on LinkedIn, and has invited you to join" while sending Joe Blogs the same invite claiming you were on LinkedIn.

8

Repair / Tektronix deprecated free trial options

« Last post by Circuitauger on Today at 03:58:46 pm »

Hello,

Been needing to get some options onto my Tektronix TDS series oscope for some signal analysis. Found Tek still has the free trial & download of the software package option on their website, installed, everything works fine. The issue however is that unfortunately it seems that Tektronix no longer actually sells license keys and/or option keys for any of their older equipment. 

So currently I’m stuck just leaving the thing on so the number of remaining code launches doesn’t decrement to 0.

Saw on the forums here there’d been discussion on hacking the scopes to unlock options, don’t know if I need to go down that road yet.   

Does anyone know how the remaining trial boot up counter works? Is it writing to some eprom, or can the hdd just be frozen in time from changes, or the trial software just indefinitely uninstalled and reinstalled?

9

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by tszaboo on Today at 03:57:30 pm »

I initially thought of it as a Facebook for work related stuff. So you could make use of the contacts you have at work and not have them see the crazy stuff you get up to at the weekend.

I avoid it mostly as it wants to be a job advertising website and is infested with agencies trying to sell me a job that I left years ago.

Some of the headhunters are completely useless. I had one that cold called me on my work phone to try to poach me. I was sitting 1.5m from my boss. Another one sent me a job profile, that "I would be a good match", that I wrote because it was an opening in my engineering department. But there are also good agents and postings on it.

10

Buy/Sell/Wanted / FS: Leader 3282 Stereo RF Sig Gen

« Last post by kloss on Today at 03:56:37 pm »

Leader LG3282 FM Stereo and AM Stereo RF Signal Generator 10 kHz to 280 MHz top of the line model with many great features. Previously used for Car Audio System development work. Included is a copy of the user manual and an Aeroflex carry case, custom designed for similar equipment. Top quality item from Japan. Tested working, calibration recently carried out so spot on frequency. £599.00 Collection or shipping available.