need to read and log 1Khz signal

[qazi ahmad]

Hi,

I have a little problem reading and logging a 1Khz signal. i am using USB DAQ6009 and i am using three of its channels. By the way i have labview2010 windows7

Problem.

I set sampling frequency to 10,000 with continuous samples on DAQmx timing vi, but it gives me correct waveform until 100Hz but when i reach to 1Khz the results were very bad i can't identify the waveform anymore.

i am posting the data i collected for different frequencies you can see the problem in it after 100 Hz.

any idea how to improve my measurment system to get correct waveform after even 1Khz.

thanks!

looking forward

[Coq_Rouge]

3 channals at 10KHz should be OK. since the max agregate sampling frequency for your unit is about 40K samples per second. So can you post your code. As we need to take a look at it, in order to help

[Tom Sedlack]

The USB-6009 is a sotware timed DAQ rather then hardware timed.  This means that the software tells the DAQ to make a measurement rather then the hardware making the measurement on its own.  I believe I read someplace that the analog output maximum update rate is 150 Hz.  I would think the analog input rate would be similar.  That is somewhat validated by the issues you are having at samples above 100 Hz.

[qazi ahmad]

I don't know it might be right that it can't do sampling beyond 150Hz, but then its really strange. anyway i am sending my Vi to here.please have a look, in my openion there is nothing wrong with it.

looking forward

[Coq_Rouge]

The AD part of the 6009 unit. Will have HW timing. And an aggregate sampling rate up to some place over 40K samples. It is the DA part that is software timed

[qazi ahmad]

Then whats wrong with the readings at 1Khz?