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university:tools:m1k:alice:oscilloscope-x-y-user-guide [25 Jun 2021 19:52]
Doug Mercer [The Top Menu Section]
university:tools:m1k:alice:oscilloscope-x-y-user-guide [29 Jul 2021 14:59] (current)
Doug Mercer [Applying Digital Filtering:]
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 =====Applying Digital Filtering:​===== =====Applying Digital Filtering:​=====
  
-With this interface, ALICE Desktop can apply digital filtering to the captured Channel A and B voltage waveform data before being displayed in the Time and/or Frequency domains. ALICE uses the numpy convolve function to perform the filtering function. It is possible to have the program generate a simple Box Car (moving average) filter by setting the length and then clicking on the Box Car check box.+With this interface, ALICE Desktop can apply digital filtering to the captured Channel A and B voltage waveform data before being displayed in the Time and/or Frequency domains. Digital filtering can also be applied to the contents of the generated AWG waveform buffers as well. ALICE uses the numpy convolve function to perform the filtering function. It is possible to have the program generate a simple Box Car (moving average) filter by setting the length and then clicking on the Box Car check box.
  
 The supplied list of coefficients is convolved with the captured data buffer. The list of filer coefficients for either Channel A or B is first loaded from a single column .csv file by using the “Load CH A Filter Coef” and “Load CH B Filter Coef” buttons. The length ( number of coefficients ) and file name will then be displayed. The digital filter(s) will be applied to the voltage waveform data buffers if the “Filter CH A” and/or “Filter CH B” checkboxes are checked. The supplied list of coefficients is convolved with the captured data buffer. The list of filer coefficients for either Channel A or B is first loaded from a single column .csv file by using the “Load CH A Filter Coef” and “Load CH B Filter Coef” buttons. The length ( number of coefficients ) and file name will then be displayed. The digital filter(s) will be applied to the voltage waveform data buffers if the “Filter CH A” and/or “Filter CH B” checkboxes are checked.
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 Alternatively,​ a formula for the filter coefficients can be entered using the CH A or CH B Filter formula buttons. The program puts up an entry window where the formula can be entered. Conventional Python syntax is used and all the math and numpy library functions are available as in the the rest of ALICE. The program looks at the arithmetic sum of the coefficients and scales them appropriately for an overall gain of 1 through the filter. Alternatively,​ a formula for the filter coefficients can be entered using the CH A or CH B Filter formula buttons. The program puts up an entry window where the formula can be entered. Conventional Python syntax is used and all the math and numpy library functions are available as in the the rest of ALICE. The program looks at the arithmetic sum of the coefficients and scales them appropriately for an overall gain of 1 through the filter.
  
-The DFiltACoef and DFiltBCoef array variable are used to store the filter coefficients. The Filter formula coefficient scaling feature can be used to scale a set of filter values read from a file. First read in the values from the file and then simply pass the array through the formula function by entering DFiltACoef or DFiltBCoef for the formula.+The DFiltACoef and DFiltBCoef ​/ AWGFiltACoef and AWGFiltBCoef ​array variable are used to store the filter coefficients. The Filter formula coefficient scaling feature can be used to scale a set of filter values read from a file. First read in the values from the file and then simply pass the array through the formula function by entering DFiltACoef or DFiltBCoef for the formula.
  
 There are many filter design tools that can be found by searching the web. Here is one that works well but we are not necessarily endorsing it over any others that might be out there: There are many filter design tools that can be found by searching the web. Here is one that works well but we are not necessarily endorsing it over any others that might be out there:
university/tools/m1k/alice/oscilloscope-x-y-user-guide.1624643522.txt.gz · Last modified: 25 Jun 2021 19:52 by Doug Mercer