08-25-2009 10:06 PM
08-26-2009 12:58 PM
Hi odessy27,
From the help, Subset and Resample will downsample the signal if you specify a larger dt or df. If you have a signal that has been sampled at 1.7 kHz, and you want to downsample to a 1 Hz signal, SignalExpress will take the samples of your signal at 1 Hz. If there is not a sample at an integer multiple, then SignalExpress will interpolate between the two closest signals.
08-26-2009 01:50 PM
jschwartz wrote:Hi odessy27,
From the help, Subset and Resample will downsample the signal if you specify a larger dt or df. If you have a signal that has been sampled at 1.7 kHz, and you want to downsample to a 1 Hz signal, SignalExpress will take the samples of your signal at 1 Hz. If there is not a sample at an integer multiple, then SignalExpress will interpolate between the two closest signals.
Jim thanks for the reply. I think I should clarify my question a little more. I am downsampling my data using the Subset and Resampling feature. My hardware (NI9239) limits minimum sampling frequency to 1.6kHz. I, then process data using scaling and conversion and adding filter (Both features does not reduce number of samples) the processed data then goes to subset and resampling where I spacify dt=1s, as a result number of samples are reduced from 1.6kSamples to 1 sample each second.
So could this whole process flow be summerized as, Acquiring Data each second (1.6kSamples)>>Scaling and Conversion(1.6kSmples)>>Filtering(1.6kSamples)>>Subset and resample(1sample) This?
If my interpretation of the process flow is correct, then how does the signal express convert 1.6kSamples of filtered data into 1 sample each second? Is it average of 1.6k Samples over one second, or the random picked sample out of 1.6k samples or 1600th/latest sample each second?
08-27-2009 06:03 PM