Meter CHA
The Meter A option provides the same functionality as the Meter A button. This makes the meter window for channel A visible.
Meter CHB
The Meter B option provides the same functionality as the Meter B button. This makes the meter window for channel B visible.
Set CHA GND Adjust
The impedance of the USB ground lead can require a small adjustment to the ground used by the oscilloscope. The Set ChA GND Adjust option enables the user to auomatically adjust the ground point for sensitive measurements. When selected, the following message will appear:
Connect a scope probe set to x1 gain and connect the probe tip and probe ground lead to an external ground reference. After clicking "OK", the scope performs a routine in which it cycles through each input gain setting the adjusted ground level.
When the ground offset has been set, the V/Div text shown on the oscilloscope display is shown on a red background.
Clear CHA GND Adjust
Selecting this option will remove any active ground level adjustment from the measurements for channel A.
Set CHB GND Adjust
The impedance of the USB ground lead can require a small adjustment to the ground used by the oscilloscope. The Set ChB GND Adjust option enables the user to auomatically adjust the ground point for sensitive measurements. When selected, the following message will appear:
Connect a scope probe set to x1 gain and connect the probe tip and probe ground lead to an external ground reference. After clicking "OK", the scope performs a routine in which it cycles through each input gain setting the adjusted ground level.
When the ground offset has been set, the V/Div text shown on the oscilloscope display is shown on a red background.
Clear CHB GND Adjust
Selecting this option will remove any active ground level adjustment from the measurements for channel B.
SignalGen
Selecting the SignalGen option from the tools menu displays the configuration window for the signal generator output (shown below).
This allows the operator to select a pre-defined waveform from
| · | DC output
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| · | Sawtooth
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| · | Square
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| · | Sine
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| · | Triangle
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| · | Pulse
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Each of these waveforms may be adjusted in amplitude, ground offset and frequency. In addition, there is an option to load a custom waveform from a .CSV file. This file should have one column of millivolt values, one for each sample. The maximum number of samples permitted is 1024. It is possible to save a scope trace to a .CSV file and then use this file as the source for the signal generator custom waveform (from channel A data). If the file contains more than 1024 data points, only the first 1024 points will be used to generate the pattern.
The signal generator operates from a 500kHz clock. The frequency dial selects a divider of between 1 and 255 that is applied to the 500kHz clock. The output frequency is also dependent on the number of samples selected. The output frequency is given by:
Output Frequency = 500kHz / (Divider * Samples)
For small divider values the output frequency changes can be large. For example:
Samples = 16 and Divider = 2 gives an Output Frequency of 15625Hz
Samples = 16 and Divider = 3 gives an Output Frequency of 10417Hz
Consequently small frequency dial changes can result in large output frequency changes, especially with small divider values. An Auto samples option is available that automatically sets the number of samples to provide a more linear response to frequency dial changes.
The output from the signal generator will not be active until the Output button is active and the scope has triggered (if it is running). Also, the signal generator output will not be available when an external trigger source is being used.
Test Mode
In test mode the EasyScope does not acquire real data but provides simulated data from a counter. This allows the communication with the PC to be verified. The display observed in test mode should always be a saw tooth type wave with clipping occurring (see picture below). The wave is at a frequency of 244.1Hz.
Test mode must be disabled to acquire real data.