2
\$\begingroup\$

I saw many videos on YouTube about displaying video signal on analog oscilloscope. Regardless of the electronic circuit and how it works, they need Z-axis.

Video on CRT display of scope

I want to do the same thing on my oscilloscope but the problem is my scope (MCP CQ620CF) has no Z-axis. I'm wondering is it possible to add Z-axis to my scope? Maybe I have to use the potentiometer of intensity knob as Z-axis, I mean the potentiometer could be a voltage divider so I can inject the voltage coming from Z-axis signal into the potentiometer pin?

\$\endgroup\$
7
  • \$\begingroup\$ Would need a schematic of the oscilloscope to know how it might be done. \$\endgroup\$
    – Carl Rutschow
    Commented Sep 18 at 13:53
  • 2
    \$\begingroup\$ If you are lucky the intensity potentiometer has a place where you can connect a disturbing voltage. BEWARE: there can be hundreds of volts to the ground and inserting something can overload the existing circuit which for example blanks the beam during the flyback period. Or there's some lowpass filtering which flushes to the drain your dream of injecting a video. Better to have a schematic or be the talented and well equipped one who can reverse engineer the circuit and design&make the insert, both without killing himself or the scope . \$\endgroup\$
    – Absus4
    Commented Sep 18 at 17:24
  • \$\begingroup\$ Have you a "blanking" input at the rear of the scope? If yes, then you can use it ... It generally has a capacitor input, so voltage should not be too "high" ... \$\endgroup\$
    – Antonio51
    Commented Sep 18 at 17:51
  • \$\begingroup\$ It seems that a Z entry exist on this scope ... ritmasaga.com.my/images/Products/MCP/TEST%20INSTRUMENTS/… Z-Axis input Zin: 47k ; Vin: 5Vp-p; Bw: DC~2MHz \$\endgroup\$
    – Antonio51
    Commented Sep 18 at 18:01
  • \$\begingroup\$ There is nothing in the back side of my oscilloscope. Only the AC power socket. – \$\endgroup\$
    – M.A.K
    Commented Sep 19 at 3:52

3 Answers 3

Reset to default
4
\$\begingroup\$

This oscilloscope model claims to have Z-axis. Sometimes, this BNC input jack is located on the back panel...
enter image description here

\$\endgroup\$
3
  • \$\begingroup\$ There is nothing in the back side of my oscilloscope. Only the AC power socket. \$\endgroup\$
    – M.A.K
    Commented Sep 19 at 3:50
  • \$\begingroup\$ No labeled BNC connector? Then your oscilloscope has no inherent Z-axis ability. I'm guessing that yours is an early version of the 'scope described above, and that Z-axis circuits were added to later models with the same part #. For you to add the high-voltage DC-isolating circuits required for Z-axis is a highly non-trivial and dangerous modification. \$\endgroup\$
    – glen_geek
    Commented Sep 19 at 11:55
  • 1
    \$\begingroup\$ Input connector or no input connector might be a way to position two models in the market instead of just one: "check the PCBs". \$\endgroup\$
    – greybeard
    Commented Oct 16 at 6:07
3
\$\begingroup\$

You'll need to find a schematic or suss it out yourself.

There will be an intensity adjustment and a retrace blanking circuit, connected to a grid or cathode.

It's possible that those circuits are very far from ground potential. Here, for example, is an oscilloscope that has the grid and cathode at more than 600VDC negative wrt ground.

CRT oscilloscopes contain circuitry at potentially lethal voltages and fault currents, and extreme care is called for.

\$\endgroup\$
0
\$\begingroup\$

Can you emulate the Z-coordinate by how long you stay at XY point?

For the scan you already have three coordinates (paprameters) to control by XY input. They are X-voltage, Y-voltage and dwell time.

You can divide you one frame in multiple drawing scans.

Then have one time-triggered loop where you load new matrix.

Inside have scanning loop where you scan over rows (X) and columns (Y) with a variable dwell time. This scan will have variable FPS.

Advance to loading new frame only when the scan is finished and new image loading is triggered.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.