This shows you the differences between two versions of the page.

Both sides previous revision Previous revision Next revision | Previous revision | ||

university:tools:m1k:alice:oscilloscope-x-y-user-guide [25 Jun 2021 19:34] 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:] |
||
---|---|---|---|

Line 57: | Line 57: | ||

===Trace Controls=== | ===Trace Controls=== | ||

- | The Curves drop down menu button allows the selection of which signal waveform traces will be displayed vs time. The All button selects all four curves to be displayed and the None button clears all four curves. Plot the Math-X and Math-Y formulas by clicking on those options. ALICE can automatically adjust the trace vertical position to center the CA-V and /or CB-V traces on the midpoint of the waveform each sweep by clicking on either or both of the options below the –Auto Vert Center- heading. | + | The Curves drop down menu button allows the selection of which signal waveform traces will be displayed vs time. The All button selects all four curves to be displayed and the None button clears all four curves. Plot the Math-X and Math-Y formulas by clicking on those options. ALICE can automatically adjust the trace vertical position to center the CA-V and /or CB-V traces on the midpoint of the waveform each sweep by clicking on either or both of the options below the –Auto Vert Center- heading. This is analogous to a software "AC" coupling mode where the "DC" level of the trace is always centered on the grid. |

When using external Resistor Divider attenuators the frequency response of the Channel may be reduced. The software High Pass frequency compensation can be selected for either channel by clicking on the buttons below the –Input HP Comp- heading. See the section on Analog Inputs below | When using external Resistor Divider attenuators the frequency response of the Channel may be reduced. The software High Pass frequency compensation can be selected for either channel by clicking on the buttons below the –Input HP Comp- heading. See the section on Analog Inputs below | ||

Line 545: | Line 545: | ||

=====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. | ||

Line 557: | Line 557: | ||

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.1624642492.txt.gz · Last modified: 25 Jun 2021 19:34 by Doug Mercer