Error

[Petar2015]

Hi,

 I ues Labview for my experiment. After a frequency sweep, I face an error, not always but %80 of the experiments. So, I mean the program doesn't have any error. The frequency sweep range is 40-70 Hz in 120 steps. The sampling rate is 90000 samples per second, I record data for 1 second every step. So, the result matrix is huge(90000*120). The RAM of the laptop is 4GB, could it be the reason?

I've attached a screenshot of the error to this email.

Vahideh

[billko]

Is there a reason for such a high sampling rate when a sampling rate two orders of magnitude lower would suffice?  (i.e., Hundreds of samples per second and not tens of thousands?)

[crossrulz]

Yeah, you are taking way too many samples.  Per Nyquist, in order to see a 70Hz signal, you need to sample at least 140S/s.  I like to use more like 10x instead of 2.  So change your sample rate to more like 1kS/s.  This will reduce the amount of memory you are using by 90x.

[billko]

Maybe catching transients at the kHz level, come to think of it?

[Petar2015]

Many thanks for your replies, actually with lower sampling rate, I can'i obtaon good result, So I have to increase the sampling rate, because only in this case my results are in the acceptable range. 

[Petar2015]

We are thinking of buying a new PC with 32Gb RAM and a good processor.but I thought, maybe it wouldn't a good solution. As you that type of PCs are expensive.

[billko]

---

@Petar2015 wrote:

Many thanks for your replies, actually with lower sampling rate, I can'i obtaon good result, So I have to increase the sampling rate, because only in this case my results are in the acceptable range. 

---

That's impossbile.  There's something wrong with the way you are acquiring the signal if that is the case.

[Petar2015]

So, what are you suggesting? I can perform the experiment without any problems, but sometimes I face this error 😞

After the experiment, when I import those matrices to MATLAB for process, it takes 5-6 minutes time. So I'm thinking of RAM

[billko]

I think you have to think about why you can't capture a good signal using the Niquist standard?  (Sampling rate twice the frequency.)  Or even 3x or 4x (280 S/s)?

Edit - or even 10x as was suggested.

Are you actually trying to capture something out of band?

[Petar2015]

It's sweep, the frequency changes from 40-70, so you mean I adjust the sampling rate to 140.?

Okay, I'm going to try it, though I've tried 1000 before.