AO Pulse Generation

[Alloush]

Dear All,

I have been trying to develop this application for several days and have posted several times on the forum in the last few days to get my application up and running. The help i received has helpful in giving me direction but unfortunately I could not acheive my aim, I might be using incorrect methodology, therefore here is what I am trying to do in detail.

1. Output an Analogue signal using ao0. The signal is an amplitude modulated sign wave (Asin(w1t)(1+sinw2t)) where wv2 is the lower frequency. Looking at the diagram attached w2 is the red wave and the amplitude modulated signal is the blue wave which is the only signal to be outputed. The waveform should be continousely outputed till i stop it (this is no problem).

2.  At the same time I would like to output a digital pulse at the zero crossing of the amplitude modulated sine wave at different phases selected by the user. The best way I thought this could be done is using the wv2 red wave as a reference which is generated at the same time as the amplitude modulated wave since its frequency is one of the frequencies used for the amplitude modulated sine wave., and trigger at the red waves zero crossing every time (therefore a trigger would be generated at both zero crossing if both are in phase) Then to trigger at a different phase with relation to the amplitude modulated wave (blue one), shift the phase of the red wave and still trigger at zero crossing but now it will be at a different phase with relation to the blue waveform.

3. I reqiure the timing to be as accurate as possible, but the frequencies I will be triggering at will be less than 300 Hz so software should be fine for this. Should i use a counter or do line?

Attached is my VI, which fails miserabely especailly when I change the the phase of wv2. I really need to finish this VI quickly as its just one peice of a jigsaw, Is what I am trying to do possible at all???? and is this the right way to tackle the problem?

I have pci 6229 card

labview 8.0

windows xp

keyboard and mouse

Thank you for your help,

Cheers

Ala

[andre.buurman@carya]

hello,

You could calculate a square wave AO 0-5V and do triggering on rising or falling edge.

I used this in a project where there was a delay in generating the sample and reading them back, the square wave with edge triggering allowed me to accurately measure the effect of deliberate disturbances in the output signal on the input from the system under test.

regards,

André

[Alloush]

Alo,

Are you suggesting that I use an AO instead of DIO or a counter line. if that is the case the problem is still the same I think.

Cheers

[andre.buurman@carya]

Hello,

It was a guess towards your problem.

It appears that I do not understand your problem.

Regards,

André

[Alloush]

Hello Everyone,

Attached is my solution, its in express but it works

Thankx,

Ala