Products > Test Equipment
Smitih Charts, still relevant in 2024?
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W4PJB:

--- Quote from: Wallace Gasiewicz on June 18, 2024, 09:47:16 pm ---Mine is an HP 8713 which I upgrades to 8714 with a EPROM change, You should read a little about these things before you buy.Here is a short Keysight Summary of the 8714 ET it includes Smith Charts:     

https://www.keysight.com/us/en/product/8714ET/rf-network-analyzer-tr.html

--- End quote ---

Thanks! I passed on this unit (price was right and it was local, only reason it was on my radar) and actually purchased an 8753C w/ 85046A S-Parameter test set last night. Seemed like a much better deal and was already upgraded to an LCD screen. The screen on the 8714 I looked at was pretty dim and burned in.
joeqsmith:

--- Quote from: paul@yahrprobert.com on June 18, 2024, 05:42:51 pm ---...
Some people still like them as a way of visualizing things, but if you're handy with Matlab, Octave, or Python you can do things quicker and way more accurately.
...

--- End quote ---

I don't see why you couldn't have your cake and eat it too.  Or, why you wouldn't.    I wouldn't want to trade in an XY graph on an oscilloscope for some digital readouts.  Same for the SA, logic analyzer....   I would rather see the waveform and for complex impedances, Smith.
Georgy.Moshkin:
When we need to visualize complex number, we can use polar plot.
E.g., in Octave

--- Code: ---handle1=plot(real(s11), imag(s11), 'Color',[1.0,0,0]);
--- End code ---
Simply using real part of s11 for x coordinates, and imaginary part for y coordinates.
This graph also can be called a Smith chart, we can add constant resistance circles, stability circles, etc.
There is no need to eliminate Smith chart, as well as polar coordinate system  :-DD

Smith chart is used in a lot of books and recognized by many people. It may help to remember some concepts. E.g., see here is Smith chart visualization of patch antenna inset length tuning compared to patch dimensions tuning: https://youtu.be/v8uxhbu36Ug?si=GXQMQTdlT_ddQQCy&t=32

When we tune inset length, we jump between resistance circles (S11 curve radius changes)
And when we change patch dimensions, we tune resonant frequency (point moves along S11 curve)

Maybe seller meant that Smith charts are no longer used in paper form to design matching circuits. A lot of CAD programs provide polar plots and call them Smith charts. Some hatred toward Smith charts is caused by unnecessary complication: drawing all those circles at different offsets and pushing into student heads. Maybe teachers should have used simple polar plots without all those circles and terminology first. So, if Seller doesn't like Smith charts, it's not his fault!

Smith chart would be especially handy if I design series-feedback oscillator, tunable impedance block (measuring S22 for FET while tuning Vgs bias).
tautech:

--- Quote from: Georgy.Moshkin on June 19, 2024, 03:23:51 am ---When we need to visualize complex number, we can use polar plot.
E.g., in Octave

--- Code: ---handle1=plot(real(s11), imag(s11), 'Color',[1.0,0,0]);
--- End code ---
Simply using real part of s11 for x coordinates, and imaginary part for y coordinates.
This graph also can be called a Smith chart, we can add constant resistance circles, stability circles, etc.
There is no need to eliminate Smith chart, as well as polar coordinate system  :-DD

Smith chart is used in a lot of books and recognized by many people. It may help to remember some concepts. E.g., see here is Smith chart visualization of patch antenna inset length tuning compared to patch dimensions tuning: https://youtu.be/v8uxhbu36Ug?si=GXQMQTdlT_ddQQCy&t=32

When we tune inset length, we jump between resistance circles (S11 curve radius changes)
And when we change patch dimensions, we tune resonant frequency (point moves along S11 curve)

Maybe seller meant that Smith charts are no longer used in paper form to design matching circuits. A lot of CAD programs provide polar plots and call them Smith charts. Some hatred toward Smith charts is caused by unnecessary complication: drawing all those circles at different offsets and pushing into student heads. Maybe teachers should have used simple polar plots without all those circles and terminology first. So, if Seller doesn't like Smith charts, it's not his fault!

Smith chart would be especially handy if I design series-feedback oscillator, tunable impedance block (measuring S22 for FET while tuning Vgs bias).

--- End quote ---
Again:

--- Quote from: tautech on June 18, 2024, 09:20:43 pm ---
Smith tells us what other sweeps cannot.
From ~900 MHz Yagi:



--- End quote ---
A Smith and a Polar, add a marker and which provides more info ?
pdenisowski:
Out of the 215 videos I have on the Rohde & Schwarz YouTube channel, the most viewed, most commented on, and most liked video is the one on the Smith Chart

And yes, a lot of our customers still use the Smith Chart :)

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