TextGear - A blog about test gear, in text...

[JackP]

Ok, so after a few false starts I've finally written my first blog post, entitled, "A Layman's Guide to Oscilloscope Jargon". Feedback appreciated, especially format/grammar/spelling/fluidity, as well as technical accuracy (mainly in the update rate section if you would). Thanks a bunch.


 

[Muttley Snickers]

I had trouble with Internet Explorer 8, probably my end, will go back in with Chrome.

Muttley

[Dave]

It's slightly confusing when you talk about sinc interpolation, while your image is showing a linear interpolation.
It may be also worth mentioning that with real sinc interpolation the scope is able to accurately reconstruct the waveform with just two samples per period.

[EEVblog]

It may be also worth mentioning that with real sinc interpolation the scope is able to accurately reconstruct the waveform with just two samples per period.

I believe you need a minimum theoretical sample rate of 2.4 times the bandwidth to accurately reconstruct a signal. You are thinking of Nyquist.

[EEVblog]

I like the look of it, but what's with the URL?
http://techrepairer.wix.com/textgear
and all the junk in the full URL:
http://techrepairer.wix.com/textgear#!1-A-Laymans-Guide-to-Oscilloscope-Jargon/c1sbz/8F3406CB-B09D-4620-AEC9-3C72895888B4

You should have a proper domain name from the get-go.

[JackP]

About the URL, if after a few posts I can see myself continuing with the blog, I will pay for the upgrade (It's only about £5-10 for a custom domain plus ad removal). I believe you get a free email as well, but I'm not sure. I've replaced the passage on interpolation with a simpler "due to processing" clause, mainly because I am not too crash hot on the subject and don't wish to supply false information; besides, for the person reading it I doubt this info is necessary or will be understood.

Sorry about you problem Muttley, I have no control over browser compatibility. Works for me in Chrome (should really test it out in others).

Thanks for the comments guys.

[Mark Hennessy]

I've not read the text yet, but I applaud the notion to produce a site that focuses on the quality of the writing. My initial thought: increase the line spacing to make it easier to read, especially for older eyes.

I played around with Firebug, which lets you modify the CSS on the fly, and reckon that 24px looks a lot better. Or ~1.5em if you prefer to avoid pixels.

(Never tried Wix, so no idea if you have that level of control).

Anyway, just a suggestion. I use 23px on my site, which is also quite wordy, but not as pretty as yours 

[rsjsouza]

Good job covering this basic area. I can see myself sending this to co-ops and students in general. Since you asked for opinions, I give some of my personal preferences about the text.

One issue I see with the flow of the article: the end of the "Bandwidth" section references analog scopes. However, IMO the first paragraph of the "Sample Rate" section should mention this is not applicable to analog scopes. The way it is currently written conveys the idea (at least to me) that sample rate is critical for bandwidth, irrespective of technology.

Still on the same section, I got a funny rendering beside the picture (check the attached picture) - in all three browsers (IE, FF and Chrome). Is this intentional as a caption to the picture?

In the "Memory Depth" section, I would have modified the sentence: " is the memory depth, which is the number of points (as I called the samples when describing the sample rate) the scope can store." to " is the memory depth, which is the number of samples (also commonly called points) the scope can store. "

Still in the same section, I would move the equation sentence to the end of the second paragraph, as you are already talking about the relationship between memory depth and sample rate. Thus the third paragraph would flow better: "heck, deeper memory gives us a better sample rate at slower timebases as shown in the equation above. However, there is a big trade-off between these two factors, and the performance of your scope"

[Mark Hennessy]

Still on the same section, I got a funny rendering beside the picture (check the attached picture) - in all three browsers (IE, FF and Chrome). Is this intentional as a caption to the picture?

Looks fine to me - your browsers aren't anti-aliasing it correctly when scaling it down. It might be an issue with the OS settings if all three browsers do the same. Are you set to 24 bit colour depth?

The original image is massive. As a rule, it's considered bad practice to let the browser scale an image - far better to manually resize it and save it as a new image. This saves a lot of bandwidth (depending on the size of the original), and avoids funnies with rendering like we're seeing here.

[rsjsouza]

Still on the same section, I got a funny rendering beside the picture (check the attached picture) - in all three browsers (IE, FF and Chrome). Is this intentional as a caption to the picture?

Looks fine to me - your browsers aren't anti-aliasing it correctly when scaling it down. It might be an issue with the OS settings if all three browsers do the same. Are you set to 24 bit colour depth?

Interesting; I am using 32-bit color depth and tested in two different laptops: Windows 7 and 8.1. One point in common is they both use the built-in Intel graphics card (different driver revs, though). I am using IE11, FF38 and Chrome 43.

[Mark Hennessy]

Still on the same section, I got a funny rendering beside the picture (check the attached picture) - in all three browsers (IE, FF and Chrome). Is this intentional as a caption to the picture?

Looks fine to me - your browsers aren't anti-aliasing it correctly when scaling it down. It might be an issue with the OS settings if all three browsers do the same. Are you set to 24 bit colour depth?

Interesting; I am using 32-bit color depth and tested in two different laptops: Windows 7 and 8.1. One point in common is they both use the built-in Intel graphics card (different driver revs, though). I am using IE11, FF38 and Chrome 43.

I'm using XP on this ancient HP DC7800, with the inbuilt Intel graphics (32 bit). Also FF 38 and Chrome 43...

[edavid]

It may be also worth mentioning that with real sinc interpolation the scope is able to accurately reconstruct the waveform with just two samples per period.

I believe you need a minimum theoretical sample rate of 2.4 times the bandwidth to accurately reconstruct a signal. You are thinking of Nyquist.

I am not sure what you are saying... by definition, a signal sampled at the Nyquist rate can be accurately reconstructed with sinc interpolation.

[JackP]

Thanks a lot guys, I've made the suggested changes to improve the flow. Interestingly, I checked the post again, and got the same formatting as mentioned earlier. This is in fact a part of the main text. Maybe I just clicked something by accident, but I couldn't get it to work in the original format, so I relocated the image to below the text. Not sure I like it, but hey-ho. 

EDIT: Mark, changed it to 1.5, is that better? What's the name of your site?

[rsjsouza]

so I relocated the image to below the text. Not sure I like it, but hey-ho. 

Now it renders quite well. 

[TMM]

I believe you need a minimum theoretical sample rate of 2.4 times the bandwidth to accurately reconstruct a signal. You are thinking of Nyquist.

I don't believe that is entirely correct. If the sinc function is long enough, Nyquist is enough. 2.4x may be a rule of thumb for practical applications where the length of the sinc FIR filter is short/inaccurate.

[Mark Hennessy]

EDIT: Mark, changed it to 1.5, is that better? What's the name of your site?

Looking good - I've still got the previous version open on a tab from yesterday for comparison, and yes, I think it looks better 

To see mine, click the globe under my avatar - then do the same for your profile

[JackP]

Accidentally spent an hour on your site! Glad you like the changes.

[JackP]

Finally, I've got my review of the dso-x 2002a up.

[JackP]

I don't really want to start a new thread about each new post, so I might just post here if that's OK. In any case, first part of the monster soldering tutorial is up (tools). Yeah, there is a lot of repeated info, but I like to think the added detail makes it a worthwhile addition to the multitude already out there. Stay tuned for more!