ELAN Home Systems ES370 manual Acquisition Modes

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2.6 Acquisition Modes

The USBscope50 can acquire waveforms in two different ways. The mode and sample interval (i.e. the time between each data point) is displayed on the main panel

2.6.1 Single Shot

In this mode, the ADC is clocked at up to 50MegaSamples/sec. Each sample is placed into the buffer and then the buffer is painted on the screen.

This mode is the one to use for non-repetitive signals i.e. single pulses, irregular bus events etc. It can also be used for repetitive waveforms.

For practical purposes the maximum frequency sine wave you can resolve is about 10MHz in this mode, giving just 5 sample points per cycle: expect to see a very “jagged” and “triangular” looking waveform when observing a 10MHz input! Drop the input frequency down to say 1MHz and you will see a nice smooth waveform.

In single shot mode the timebase can be set from 200ns/div all the way up to 4s/div. The time to acquire the waveform gets noticeably slower when rates above 40ms/div are selected: the total acquisition time is approximately “30 x timebase” so at 4s/div, the display will update once every 120s, or 2 minutes !

As with all digital storage scopes, be careful not to view a high frequency waveform on too low a timebase. You may see a waveform that looks correct but drifts or fluctuates over time, and that has the wrong frequency…this is called aliasing and is quite normal. To avoid this effect, always pick the fastest single shot timebase consistent with being able to view the waveform in question.

Elan Digital Systems Ltd.

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USBscope50 USER’S GUIDE Iss5

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Contents USER’S Guide Contents Hardware Specification Page Overview General Figure below shows a simplified diagram of the USBscope50 Using More Than One USBscope50 This is a safety critical point so please note it carefully Disassembling The Stack USB Connections For Stacked Configurations Repeat this for each channel in the stack to identify them Stacking Do’s And Don’ts Input Ranges Probe Compensation USBscope50 USER’S Guide Iss5 This Acquisition Modes Random Interleaved Sampling USBscope50 USER’S Guide Iss5 Trigger Modes Normal Triggering Trigger Position USBscope50 USER’S Guide Iss5 10Trigger Threshold USBscope50 USER’S Guide Iss5 12FFT Plot Spectrum Analyser 13Math Functions 14Data Export Data for CH FFT for CH Before plugging in the hardware USBscope50 USER’S Guide Iss5 Windows 2K and XP17 Page Power Requirements Performance Static Performance Dynamic Performance
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