Want to have Z-modulation on a Lissajous for a defined period by another signal

[estee]

I want to have a Z-Modulation on a Lissajous figure.This means that I could make the beam off/on for a defined period by using another signal. I need an example to simulate a cathode ray tube with beam off/on provision. For this a seperate Z-signal (square wave) can be simulated.

Please help and guide. I am using LabView 7.0 Express.

[altenbach · Accepted solution]

Make the z array alternate between Nan and 0, then add your z-array to your xy data before plotting.

• Whenever z is NaN, no values will be graphed.
• Whenever z is zero, the xy data will be graphed unaltered.

See if this works for you.

[estee]

Thanks for your valuable guidance.

Could you please elaborate and send a similar example vi if possible.

I would highly appreciate.

[altenbach]

Sorry, I no longer have access to LabVIEW 7.0.

Do you already have a complete VI that is only missing the z modulation? If so, please attach it and I will probably be able to tell you what to modify.

[estee]

Thanks for your special interest and prompt reply.

I have attached my file which could create a lissajous figure.

However, this only uses two signals ie X and Y.

How can I provide a Z-modulation? I am not able to do this.

[altenbach]

If you would create a square wave for your z-modulation it will alternate between -1 and 1 by default. Just take the square-root of it an multiply it with your x or y signal to generate NaN where z was -1, while leaving the rest of the points unchanged.

See image for a quick draft.

Message Edited by altenbach on 10-07-2008 07:36 AM

[estee]

Excellent solution Altenbach! Thanks a lot.

I have attached my new modified file which has been created according to your instructions.

This is for the benifit of everybody.

Can I do some signal calculation? For example to calculate the difference ( in degress) between the Z-modulated signal and the highest point of the figure.

Could you provide some guidance if possible?