I am looking for a code that will help me filter the data I am dealing with. I need to apply the filter to approximately 600 files and would rather not have to do each individually. I am looking for a code that can perform a low pass filter with a cut off frequency of 2 and a sampling frequency of 2000 and order 2. Cascade (direct form II). Any help would be greatly appreciated.
For lack of further details in your query, I suggest you look at Igor's built in filter operation:
DisplayHelpTopic"FilterIIR"
There is a section devoted to Cascaded Bi-Quad Direct Form II Implementation. You will have to determine your filter coefficients, and write your own simple code to sequentially select the waves you need to filter.
[quote=s.r.chinn]
...write your own simple code to sequentially select the waves you need to filter.[/quote]
If you already have all of your data in Igor, one possibly simple approach would be to put all 600 1-D waves into a 2-D wave using "Concatenate" with each column representing a different data set. Then after setting up the FilterIIR filter, the filter could be called with the DIM=0 flag (i.e. FilterIIR/DIM=0) which applies the filter to each column. Then you'd need some short code to pull out each column ("q") into either a 1D wave or print to a file, depending on what you're trying to do.
There is a section devoted to Cascaded Bi-Quad Direct Form II Implementation. You will have to determine your filter coefficients, and write your own simple code to sequentially select the waves you need to filter.
August 9, 2016 at 09:57 am - Permalink
...write your own simple code to sequentially select the waves you need to filter.[/quote]
If you already have all of your data in Igor, one possibly simple approach would be to put all 600 1-D waves into a 2-D wave using "Concatenate" with each column representing a different data set. Then after setting up the FilterIIR filter, the filter could be called with the DIM=0 flag (i.e. FilterIIR/DIM=0) which applies the filter to each column. Then you'd need some short code to pull out each column ("q") into either a 1D wave or print to a file, depending on what you're trying to do.
August 9, 2016 at 10:20 am - Permalink