smoothly change

[mauro81]

hi,

i need to create a sinewave and change smoothly the frequency or amplitude while the sinewave itself is generated  .

i found an example called 'function generator.vi' in which you can change smoothly frequency and amplitude because there is an hand-operated control of the parameters (amplitude and frequency).

my problem is that: i want an automatic control (not hand-operated),i mean ,if the amplitude is automatically changed from a value to another ,the change is sudden. how can i make smoothly this change?

[smercurio_fc]

Are you talking about the "Function Waveform Generation" VI or the "Function Generator" which is a DAQ-based VI? Do you think it's smooth based on the amount of change of the controls? Because that's really the only thing that's affecting the smoothness of the transition. Both VIs look for changes in the values and create a new waveform based on the new values, whatever they are. There's no additional code that creates a ramped change in that parameter based on what the amount of change is. Can you be a little more specific on "smooth"?

[Aitortxo]

Hi, Mauro

Have a look at this VI to see if it helps.

There is an external loop that would be your program, and inside

One button to activate the ramp
Three numeric buttons to configure the ramp
Start Value
End Value
ms Ramp

When you press Activate Button, the ramp generation starts
When the EndValue is reached, or when Activate Button is depresed the ramp generation ends.

You can build a SubVI with references for Activate Button and Current Value to fit in your VI

Hope it helps,

[mauro81]

with 'smooth' i mean one sinewave that change amplitude between one value to another not suddenly but in a lenght of time(a sort of transient!),like a linear ramp should be good.  is it possible?

i'm thankful for the .vi you sent me but i work with abview6.1 and the .vi you sent me work only with labview7.1.

 function generator.vi permits to change smoothly the amplitude in the time,but if replace the hand-operated control of the amplitude with a normal automatic control when i change the amplitude the change is sussun.

[mauro81]

sorry,the last word is sudden!

[Dennis_Knutson]

If you want to ramp your signal, why not try the Ramp Pattern function? It's on the Analyze>Signal Processing>Signal Generation palette.

[krithika]

Will it be possibel for you to convert the Vi to 7.0 version?  Or post a snap short of the block diagram?

Thanks

Krithika

[devchander]

The 'generate ramp.vi' posted by Aitortxo, converted to labVIEW 7.0

hope it helps