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Phil Mayes

SUMMARY

Pydatascope is a program to display data from a source in real time.

NOMENCLATURE

  • sample is an integer value from a data source
  • plot is a visual representation of samples from a particular data source;
    it shows values on the y-axis; time, sequence or frequency on the x-axis
  • chart is the area on which one or more plots are drawn

SOURCES

The sources supported are:

  • d2xx:

    A hardware device capable of supplying multiple channels. Each channel is drawn as a separate plot. Contact JRM Consultants for more details.
  • d2xx_socket:

    A socket supplying d2xx data.
  • file:

    One or more text files containing integers.
  • socket:

    A socket supplying integers (as text) separated by whitespace.
  • audio:

    The default microphone on the computer.

The sources are given in order of preference in the configuration file data\pydatascope.cfg. They can be edited and re-ordered via Menu > Files > Sources. See that dialog for more details.

ON-SCREEN CONTROLS

SINGLE CHART

Selects whether to show every plot on a different chart, or all plots on a single chart.

INDEPENDENT

When more than one plot is displayed on a single chart, the question arise of how to scale the plots. For example, two plots with data ranges of 100-200 and 800-900 are plotted, the chart range will be 100-900 and the plots will occupy the top and bottom 12.5%. Selecting "Independent" will make each plot occupy the full height of the chart, but y-values will not be shown. Pause tracing and click on the chart to see the y-values.

SCALING

Scales the input in one of three ways:

  • Auto (visible)

    The plots visible on the screen are scaled to fit the chart, allowing for 5% top and bottom.
  • Auto (all)

    The total data collected are scaled to fit the chart, allowing for 5% top and bottom.
  • Manual
    • Base sets the value for the bottom of the chart.
    • Range sets the scale of the y-axis.
SMOOTHING

Generates a second plot in grey, showing the average of the last N values.

AVERAGE

Accumulates N values, take their average, and plot it as a single point.

HORIZONTAL SCALE

Controls how many points / time / frequencies are plotted on the x-axis.

DISPLAY SAMPLES

Successive samples are plotted on the x-axis

DISPLAY TIME

The approximate arrival time of samples is plotted on the x-axis.

DISPLAY FREQUENCY

A [Frequency Analysis] is plotted on the x-axis. When this option is selected, the scaling controls are replaced by the following two.

SAMPLE SIZE (SECS.)

When frequencies are being displayed, this selects the latest N seconds of data for analysis.

HIGH PASS (Hz)

When frequencies are being displayed, the most prominent frequencies are displayed as green text. This sets a lower limit on what frequencies are displayed.

SHIFT

When the shift key is down, actions apply to all charts.

CHARTS

The currently active chart has a white background; others a blue-grey. Click on an inactive chart to make it the active one. The scaling controls and display type apply to the active chart. To apply them to all charts, hold down the shift key when using the controls.

LICENSE

GPL3, see COPYING.txt

VERSION HISTORY

See changes.txt

FEEDBACK

Jon Miller: jmiller at jrmconsultants.com
Phil Mayes: phil at philmayes.com


Related

Wiki: Frequency Analysis