sampling analog signal- Sample and Hold!

[traceabc]

okay..let me try and get back to you

Thanks 🙂

[traceabc]

Okay ..I tried this, still facing some problems ..here take a look at vi attached..also, if we interpolate that means the actual Ts is changing and we are

getting value at something other than what we are trying to get at Ts, isn't it so? Isn't there any other way?

Also, I am still not getting how to rebuild 🙂

[Brian_P]

traceabc, 

I am sorry that you are having issues with your program.  I believe the reason that your rebuild is not working correctly is that you are only inputing one point into that array, so the array is plotting only the one point. Try wiring the original Y array into the new array, this will keep the same amplitudes and then give it a new dt.

Also with interpolation I believe they mean that you are only going to get points at your specified sampling interval, and then in order to get anything in between you will have to interpolate between points.  So the Ts will remain the same.

I hope this helps.

Regards,

Brian P.

[traceabc]

Thanks for the tip..let me try this out!!

I have been able to do quantization, binary+line coding of the signal..but the only thing I am still having problems is doing sampling (1st stage, what is required before quantization of a signal) ...theoratically to sample a signal we multiply an impulse train (with Ts interval )with the signal and perform sampling..I know this is just theoratical... But still having issues on how to implement in labview praactically any help or alternative ideas???

[johnsold]

Any signal you have in LV is ALREADY sampled.  It is stored as an array of datapoints, usually measured (or calculated) at fixed time intervals, dt.  The array may be further encapsulated into a waveform datatype.

When you are simulating the sampling process you only have access to the original samples.  The simplest approach ( which you have already learned is not too versatile) is to use every nth sample from the original array.  Otherwise you must interpolate between samples to get sampling rates which are not factors of the original sampling rate.

How to do this practically? Calculate the times of the desired (new) samples. Calculate the indexes of the points in the original array which are on either side of the first new sample.  Interpolate.  Repeat for the next new sample time.

Lynn

[capricorn815]

sir, i am making power analyzer using sound cards. i find power factor and signal wave forms. i am facing some problem in VI. 1. 3phase wave form did not exact 120 degree out of phase. 2. power factor daviate with increment or decrement by 0.01 continously. i am attaching my vi file please help me for stabling and finding exact wave form phase difference and power factor measurement.

[RavensFan]

Your question has nothing to do with the message thread you posted into.

Please stick with your other thread.  http://forums.ni.com/t5/LabVIEW-Electrical-Power-Suite/power-analyzer-using-usb-sound-card/m-p/24903...