Thread: Down-sampling

Started: 2016-05-09 21:30:55
Last activity: 2016-05-10 14:19:41
Topics: SAC Help
Abhash Kumar
Down-sampling
2016-05-09 21:30:55
Hi,
I want to down-sample my data from 100 samples/second to 40
samples/second. As per the SAC manual, decimate function has only integral
factor (from 2 to 7) to down-sample the data. Is there any possible way to
use decimate function or any other function to down-sample from 100 to 40
samples/second. I would be grateful for any suggestion in this regard.

Thanks
Abhash Kumar

  • Arthur Snoke
    Re: Down-sampling
    2016-05-09 22:08:32
    For a resampling like yours, I would use interpolate. If there is a lot of energy near the Nyquist, you need to low-pass filter it first. Download the SAC manual and search on interpolate .

    On May 9, 2016, at 2:31 PM, Abhash Kumar <abhash.kumar84<at>gmail.com> wrote:

    Hi,
    I want to down-sample my data from 100 samples/second to 40 samples/second. As per the SAC manual, decimate function has only integral factor (from 2 to 7) to down-sample the data. Is there any possible way to use decimate function or any other function to down-sample from 100 to 40 samples/second. I would be grateful for any suggestion in this regard.

    Thanks
    Abhash Kumar

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  • George Helffrich
    Re: Down-sampling
    2016-05-10 14:19:41
    Dear All -

    * 100 sps test data: Upsample to 200 sps, downsample to 40 sps
    FUNCGEN SEISMOGRAM; INTERPOLATE DELTA 0.005 ; DECIMATE 5

    On 10 May 2016, at 03:31, Abhash Kumar <abhash.kumar84<at>gmail.com> wrote:

    Hi,
    I want to down-sample my data from 100 samples/second to 40 samples/second. As per the SAC manual, decimate function has only integral factor (from 2 to 7) to down-sample the data. Is there any possible way to use decimate function or any other function to down-sample from 100 to 40 samples/second. I would be grateful for any suggestion in this regard.

    Thanks
    Abhash Kumar

    ----------------------
    SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)

    Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
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    George Helffrich
    george.helffrich<at>bris.ac.uk


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