Operators Manual Owner manual

Operator's Manual

Sampling Modes

Real Time Sampling Mode

Real Time sampling mode is a series of digitized voltage values sampled on the input signal at a uniform

rate. These samples are displayed as a series of measured data values associated with a single trigger

event. By default, the waveform is horizontally positioned so that the trigger event is time zero on the grid.

The relationship between sample rate, memory, and time can be expressed as:

Capture Interval = 1/Sample Rate X Memory

Capture Interval/10 = Time Per Division

In Real Time sampling mode, the acquisition can be displayed for a specific period of time (or number of

samples) either before or after the trigger event occurs, known as trigger delay. This allows you to isolate

and display a time/event of interest that occurs before or after the trigger event.

l Pre-trigger delay displays the time prior to the trigger event. This can be set from a time well before

the trigger event to the moment the event occurs, up to the oscilloscope's maximum sample record

length. How much actual time this represents depends on your timebase setting. When set to the

maximum allowed pre-trigger delay, the trigger position (and zero point) is off the grid (indicated by

the trigger delay arrow at the lower right corner), and everything you see represents pre-trigger

time.

l Post-trigger delay displays time following the trigger event. Post-trigger delay can cover a much

greater lapse of time than pre-trigger delay, up to the equivalent of 10,000 time divisions after the

trigger event occurred. When set to the maximum allowed post-trigger delay, the trigger point may

actually be off the grid far to the left of the time displayed.

Usually, on fast timebase settings, the maximum sample rate is used when in Real Time mode. For

slower timebase settings, the sample rate is decreased so that the maximum number of data samples is

maintained over time.

Roll Mode

Roll mode displays, in real time, incoming points in single-shot acquisitions that have a sufficiently low

data rate. This mode can be invoked for slow acquisitions where the time per division is 100 ms/div or

slower. Roll mode samples at ≤ 2.5 MS/s.

The oscilloscope appears to "roll" the incoming data continuously across the screen until a trigger event

is detected and the acquisition is complete. The parameters or math functions connected to each

channel are updated every time the roll mode buffer is updated, as if new data is available. This resets

statistics on every step of Roll mode that is valid because of new data.

NOTE: If the processing time is greater than the acquire time, the data in memory is overwritten. In this

case, the instrument issues the warning, "Channel data is not continuous in ROLL mode!!!" and rolling

starts again.

RIS Sampling Mode

RIS (Random Interleaved Sampling) is an acquisition technique that allows effective sampling rates

higher than the maximum single-shot sampling rate. It is used on repetitive waveforms with a stable

trigger. The maximum effective RIS sampling rate is achieved by making multiple single-shot

acquisitions at maximum real-time sample rate. The bins thus acquired are positioned approximately 8

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