Resampler

Resampler IO The Resampler I/O resamples the source's data to decrease or increase the sample frequency (and record length with the same ratio) of a signal. This can be useful when several signals are sampled with a high sample frequency and record length but not all of them require this high speed and record length.

When using an RPM I/O to determine the speed of an engine, the sample frequency must be around 10 kHz or higher to get the accurate rpms. Once the speed has been determined, it can be resampled to a lower sample frequency, for example 10 Hz, because the speed will vary relatively slow. This decreases the amount of data (or file size) by a factor 1000.

Properties and actions

To control the behavior of the Resampler I/O, several properties and actions are available. These can be accessed through a popup menu which is shown when the I/O is right clicked.

Out/In ratio

The Out/In ratio property defines the ratio between the output sample frequency and the input sample frequency. Several standard values are available, as well as a user defined setting. When the sample frequency of the input signal changes, the sample frequency of the output signal will change accordingly.

Sample frequency

The Sample frequency property sets the output sample frequency of the Resampler I/O to the specified value. Several standard values are available, as well as a user defined setting. The Out/In ratio will be calculated automatically, based on the sample frequency of the input signal. When the sample frequency of the input signal changes, the sample frequency of the output signal will remain the same, a new ratio will be calculated.

Method

The Method property determines how the data is resampled:

Normal

  • When the ratio is smaller than 1, only one sample of the input data is used for each output sample.
  • When the ratio is greater than 1, several samples in the output data are filled with each input sample.
IN ratio OUT
 
Original 100 samples → 1/10 → Result 10 samples normal
100 Samples 10 Samples
 
Original 10 samples → x10 → Result 100 samples normal
10 Samples 100 Samples

Linear

  • When the ratio is smaller than 1, the mean value of several samples of the input data is used for each output sample.
  • When the ratio is greater than 1, the output data is a linear interpolation of the input data.
IN ratio OUT
 
Original 100 samples → 1/10 → Result 10 samples linear
100 Samples 10 Samples
 
Original 10 samples → x10 → Result 100 samples linear
10 Samples 100 Samples

Common properties and actions

Alias

You can change the displayed name of an object by giving it an Alias. This can be handy when you are dealing with a lot of objects and have problems keeping them apart. You can for example give channel one of your instrument the alias "Battery", when it is measuring a battery voltage. To give an object an alias, use the item Alias ... in its menu. To remove an alias and revert to the original name of the object, set the alias to an empty string.

Color

When multiple sources or I/O's are displayed in a graph or a meter, they can be distinguished from each other by their Color. Three different color settings are available for a source or an I/O.

  • Automatic
    A color is selected from a group of colors. There are separate groups for channel colors and source colors. The groups can be configured in the program settings. Each new channel or source uses the next available color in the group. When the last color in the group is used and another channel or source is added, picking will start at the top of the group again.
  • As source
    This setting is only available for I/O's. The I/O will use the same color as its source. When multiple sources are connected to the I/O, the color of the first connected source is used.
  • User defined...
    The color of the source or I/O is user selected, using a color picker dialog. Any color can be used.

Disconnect all sources

To disconnect all sources from an I/O or Sink at once, use the Disconnect all sources action.

Disconnect sink(s)

To disconnect one or more sinks from an I/O or Source, use the Disconnect sink(s) action. This will show a dialog that lists all connected sinks. Individual sinks can then be selected and disconnected from the object.

Disconnect all sinks

To disconnect all sinks from an I/O or source at once, use the Disconnect all sinks action.

Clone

When a new object is to be created, similar to an already existing object, with the same properties, the Clone action can be used. This will create an identical copy of the original object, with the exact same properties. Source(s) and sink(s) of the new object are not yet connected.

Delete

The Delete action deletes a source, I/O or sink. All connections of the object will be disconnected and then the object will be removed from the object tree. The source property of the objects that used this object as source will be cleared. The sink property of the objects that used this object as sink will be cleared. An axis in a graph that was connected to this object will be also deleted.

Export data

The Export data action allows to export the data of an object to a file. This is detailed described on the page about Exporting data.

Load

The Load action allows to load the settings and data for an object from a TPS or TPO file. This is detailed described on the page about Loading into selected objects.

Save as

The Save as action allows to save the settings and data of one or more objects to a TPO file. When multiple objects are selected, the connections between the objects are saved as well. This is detailed described on the page about Saving objects to a TPO file.