Oscilloscope

This figure displays the main program window when operating in the oscilloscope mode. On the center of the window there is a work screen where oscilloscope displays are shown, red oscilloscope display corresponds to channel A and blue one corresponds to channel B. To the left of the work screen frame there is a voltage scale of channel A (red font), to the right of the frame there is a voltage scale of channel B (blue font). Values of both voltage scales are always expressed in volts. Beneath of the work screen there is a time base (trace).

To the left and right of the work screen there are two cursors and that allow shifting zero of channel A and channel B accordingly. It is expedient to shift zero if the waveforms of both channels overlap on one another too much that complicates their analysis. To install one of 9 zero standard positions you need to right click on the corresponding cursor and then to select one of the possible values of zero positions from the pop-up menu.

There are two markers and above the work screen frame that are to perform the correct measurement of time intervals and voltage amplitude values of each channel. Markers can be moved with the mouse, you need to left click on the triangle and then when holding the left button to move the mouse to the left or right. When moving the marker within the work screen the signal parameters below the marker will be displayed on the panel .

To set the triggering level, two horizontal markers and are used. Marker sets the trigger voltage level (amplitude) of channel A, which is used when triggering (absolute) with the channel A. Marker B similarly sets the level used when triggering with channel B. Triggering markers are moved by clicking and dragging on them and . Moreover, upon moving the trigger markers, the the level set is correctly displayed on status bar. Note that if the trigger level is outside the range of voltages in the signal, USB oscilloscope may respond slowly - because it lacks a trigger (normally it will take a few seconds or less to display measurements). If this happens, press 'stop' and reset the trigger value for the triggering channel.

The Oscilloscope chart can be moved inside of the work screen by the standard scroll bar . When changing the time base or zoom, the previous oscilloscope displays may not completely fit inside the work screen, and the slider will get smaller than the scroll bar proportionally with the oscilloscope display length within the work screen to the total oscilloscope display length ratio. There is a small button below the scroll bar that allows hiding the oscilloscope settings panel that allows more area for the work screen.

The voltage scale range of channel A/B can be set on the panel / "Channel A/B (Volt/Screen)". Scale range is set by knob (see for details). It is necessary to note that USB oscilloscope supports two input ranges 0-2 V and 2-20 V by hardware. It follows that to show the most reliable oscilloscope display, which amplitude is within ±2 V it is expedient to select scale range ±2 Volt/Screen or lower. As the turning error within scale range ±2 Volt/Screen and lower will total 4V/1024 = 0.0039 V (capacity 10 bits) while within scale range ±5 Volt/Screen and higher the turning error will be 10 times larger 40V/1024 = 0.039 V. On/off buttons for the channels are positioned on the same panels. If when analyzing the device it is not required to analyze two analog signals concurrently then it is expedient to turn off one of the channels that will allow increasing the maximum sampling frequency 100 KHz to 200 KHz.

Panel "Period" allows setting the sampling period (time base) within which the analog input digitization starts. For normal previewing the oscilloscope display it is recommended that the sampling frequency is at least 5-6 times higher than the maximum input frequency. In addition to select time base on the panel "Period" you can set the oscilloscope display zoom, i.e. stretch the oscilloscope display up to 4 times for the time base for more detailed analysis, e.g. of any signal time parameters without any change in sampling period. In the upper right corner of the panel "Period" there is information about the reading mode (if enable): buf - reading with microcontroller internal buffer, pipe - pipe reading in computer (sample buffer size increases several times but requirements to the computer are getting tighter (see for details about the reading modes)). Minimum/maximum period that allows determining the reading mode is set in the Settings window. Double left click on the markup with reading mode information opens the Settings window similar to the Service/Setup.

All the triggering control elements except for the markers are positioned on the panel "Triggering" . On/Off button allows turning on and off triggering. A and B buttons select the channel and corresponding marker, that is, which signal will be used as triggering source. Ext button selects an external source for triggering that is connected to the channel B.5 of logical analyzer (external triggering is available only when buffer reading). Select edge buttons determine which signal edge (rising or falling) will be used for the absolute triggering, which signal step (rising or falling) will show the differential triggering and which external sync pulse edge (rising or falling) will show the external triggering. Two buttons positioned beneath the panel determine the triggering type: absolute or differential. An input field near the differential triggering settings button determines the difference between the adjacent waveform samples and if exceeded then the triggering condition is met.

Note that when setting the triggering parameters, if they cannot be met, e.g. if given trigger level is 5 V and maximum signal amplitude does not exceed 2 V, the device will be continually wait for the triggering condition, and will appear to 'freeze'. One of the start measurement buttons (single/cyclic) will be red. In this case it is necessary to stop measuring by pressing the respective Stop button. Adjust to troigger level to fall within the range of the signal, and re-take the measurement.

On the panel "Signal parameters below markers" the position of each marker within the time base and signal amplitude of both channels below each marker are displayed. Markers time difference and signal amplitude is also calculated, at that the difference result color is determined by the color of marker, which corresponding value is larger.

On the panel "Common signal parameters" the calculated values of DC and AC voltage component are displayed and if possible, frequency value for each channel as well.

Panel "Filtering" ensures connection and calculation of digital filters for each channel. To turn on filtering for the channel it is first necessary to calculate the filter when opening the filter settings window while pressing the "..." button and then tick off On for the selected channel.

To display traces of the signal, press the Single button or the Cyclic button on the panel "Control" .

The Single button takes only one measurement (sample digitization and accumulation by microcontroller and then their transmission to shell when operating via buffer), and then the newly read oscilloscope displays are shown on the work screen.

The Cyclic button carries out similar actions except that upon completing the measurement a new measurement starts automatically.

Upon pressing either of the start buttons (single/cyclic) the respective changes its name to Stop and becomes red colored. Pressing this 'stop' button causes an immediate device reset and a wait for result measurement termination. The stop button may be the only means to stop measuring, e.g. when the triggering level is set inapropriately.