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Depending on the timebase, any of three sampling modes
can be chosen: Single-Shot, Random Interleaved Sampling
(RIS) or Roll Mode. Furthermore, for timebases suitable f or
either Single-Shot or Roll Mode, the acquisition memory can
be subdivided into user-defined segments to give Sequence
Mode. Channels can also be combined to boost sample rate
and record length.
6LQJOH6KRW Single-Shot is the digital oscilloscope’s basic acquisition
technique and other timebase modes make use it.
An acquired waveform consis ts of a series of measured voltage
values sampled at a uniform rate on the input signal. The
acquisition, a single series of m easured data values associated
with one trigger event, is typically stopped at a fixed time after the
arrival of the event, this being determined by the trigger delay.
The time of the trigger event is measured using the timebase
clock. The horizontal position of a waveform is determined using
the trigger event as the definition of tim e zero. Waveform dis play
is also carried out using this definition.
Because each channel has its own ADC, the voltage on each
input channel is sampled and measured at the same instant. This
allows very reliable time measurements between different
channels.
Trigger delay can be selected anywhere within a range that
allows the waveform to be sampled f rom well before the trigger
event up to the moment it occur s (100 % pre-trigger), or at the
equivalent of 10 000 divisions (at the current time/div) after the
trigger.
For fast timebase settings the ADCs’ maximum single-shot
sampling rate is used (on one and each channel, with higher
sampling rates achieved by combining channels —
). For slower timebases, the sampling rate is dec reased and
7–4
the number of data samples maintained. (
).
details
See Appendix A for
see page
²
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NOT AVAILABLE WITH
9304C, 9310C, 9314C
SERIES
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When using slow timebases, sample-rate decreases and very
short events such as glitches can be missed if they occur
between two samples. To prevent this, a spec ial circuitry called
the Peak Detect system can be switched on (
menu, page 7–5
of 2.5 ns. This is done without destroying the underlying,
simultaneously captured data, on which a wide range of
advanced processing can be performed.
RIS 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 sampling rate of 10 GS/s can be
achieved by acquiring 100 single-shot acquisitions, or bins, at
100 MS/s using the 9304C, 9310C, 9314C Series oscilloscopes;
20 bins at 500 MS/s when using the other models. These bins
are positioned approximately 0.1 ns apart. The process of
acquiring this number of bins and s atisfying the tim e constr aint is
random. The relative tim e between ADC sam pling instants and
the event trigger provides the necessar y variation, measured by
the timebase to 10 ps accuracy.
) to capture the signal envelope with a resolution
see “Channel Use”
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On average, 104 trigger events are needed to complete an
acquisition. But sometimes many more are needed. These
segments are interleaved to provide a waveform c overing a time
interval that is a multiple of the maximum single-shot sampling
rate. However, the real-time interval over which the waveform
data are collected is orders of m agnitude longer and depends on
the trigger rate and the desired level of interleaving. The
oscilloscope is capable of acquiring approximately 40 000 RIS
segments per second.
5ROO Single-shot acquisitions at timebase settings slower than
0.5 s/div (10 s/div for traces with more than 50 000 points) have
a sufficiently low data rate to allow the display of the incoming
points in real time. The oscilloscope shows the incoming data
continuously, “rolling” it across the scr een, until a trigger event is
detected and the acquisition completed. T he latest data is used
to update the trace display in the same manner as a s trip-chart
recorder. W aveform Math and Param eter calculations are done
on the completed waveforms.
1RWH
The behavior of , ,
and
is modified in
Roll Mode and Sequence Modes (refer to previous chapter
and pages 7–8 and 7–9).
6HTXHQFH Sequence Mode is an alternative to single-shot acquisition that
offers many unique features. T he complete waveform c onsis ts of
a number of fixed- size segm ents acquired in Single-Shot Mode
see Appendix A for the limits
(
), which are able to be selected. .
The dead time between the trigger events for consecutive
segments can be kept to under 50 µs — in contrast to the
hundreds of milliseconds normally found between consecutive
single-shot waveforms. Complicated sequences of events
covering a large time interval can be captured in fine detail,
1RWH
to ensure low deadtime between segments, buttonpushing and knob-turning is to be avoided during
sequence acquisition.
ignoring uninteresting periods between events. And time
measurements can be made between events on different
²
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7LPHEDVH0RGHVDQG6HWXS
segments of a sequenc e waveform using the f ull prec ision of the
acquisition timebase.
Trigger-time stamps are given for each of the segments in the
“Text & Times Status” menu. Each individual segment can be
displayed by Zoom, or used as input to the MATH functions.
Sequence Mode can be used in remote operation to take full
advantage of the scope’s high data-transmission capability:
overlapping transmission of one waveform with its successor’s
acquisition (
The timebase setting in Sequence Mode is used to determine the
acquisition duration of each segment, which will be 10 x
TIME/DIV.
Timebase setting, desired number of segments, maximum
segment length and total available memory are used to
determine the actual number of samples/segment and time/point.
The display of the complete waveform with all its segments may
not entirely fill the screen.
Sequence Mode is normally for acquiring the desired number of
segments and term inating the waveform acquisition. It can also
be used to acquire the segments continuously, overwriting the
oldest ones as needed, with a manual STOP order or timeout
condition being used to terminate the waveform acquisition.
see the Remote Control Manual for details
).
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NOT AVAILABLE WITH
9304C, 9310C, 9314C
SERIES
The ADCs can be interleaved to boost standard sampling rate
and record length considerably.
When channels are combined on two-channel models, both
channels are paired on Channel 2, while Channel 1 is disabled.
On four-channel models, the two pairs of channels are enabled
on Channels 2 and 3, while Channels 1 and 4 are dis abled. Both
maximum s ampling rate and record length are doubled us ing this
function, activated by menu selection (
On fast timebases it is even possible to again double the
sampling rate by means of a spec ial adapter . With this adapter in
place, the oscilloscope interleaves the four ADCs and the
acquisition memor y to ac hieve the maximum s ampling rate and
up to four times the initial record length (
).
details
²
see page 7–8
see Appendix A for
).
Page 5
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7,0(%$6( Press
À Single-Shot or Interleaved (RIS) sampling
À External clock
À Channel pairing (combining) and Peak Detect ..
À Sequence Mode
À Number of segments in Sequence Mode
À Maximum record length.
The “TIMEBASE” menus also s how the number of points acquired,
the sampling rate and the total time span.
6DPSOLQJ
For selecting either of the two principal modes of acquisition:
À “Single Shot” — displays data collected during successive
single-shot acquisitions from the input channels. This mode
allows the capture of non-recurring or very low repetition-rate
events simultaneously on all input channels.
À “RIS” (Random Interleaved Sampling) — achieves a higher
effective sampling rate than Single-Shot, provided the input
signal is repetitive and the trigger stable.
6DPSOH&ORFN
To select “Internal” or External (“ECL”, “OV”, “TTL”) clock modes
see next page
(
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To select for channel pairing and, on models with this feature, to
control Peak Detect Mode (
6HTXHQFH
For turning “Off” or selecting “Sequence” or “Wrap” Mode.
page 7–9
5HFRUGXSWR
For selecting the maximum number of samples to be acquired, using
the associated menu knob.
to access and choose:
).
(NOT AVAILABLE WITH 9304C, 9310C, 9314C SERIES)
refer page 7–2
.
).
See Appendix A for model maximums.
See
²
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7LPHEDVH0RGHVDQG6HWXS
7,0(%$6((;7(51$/ — appears when an External clock mode is chosen.
6DPSOLQJ
This menu is inactive when the external sample clock is being used. Only
single-shot acquisition is available (
see below
6DPSOH&ORFN
For selecting a description of the signal applied to the EXT BNC
connector for the sam ple clock up to 100 MHz. The rising edge of the
signal is used to clock the ADCs of the oscilloscope. The effective
thresholds for sampling the input are
*
:
ECL ...................................... −1.3 V
0V ........................................ 0.0 V
TTL....................................... +1.5 V
).
(With CKTRIG Option ONLY)
RP (Rear Panel) specifies that
the 50–500 MHz external clock connected to the rear panel be
used as the sample clock (
CKTRIG Manual
for details
see
([WHUQDO
To select the input coupling for the external clock signal.
6HTXHQFH
Offers Sequence Mode. T he corresponding knob is used to adjust the
number of segments. Neither the trigger time stamps nor the AUTO
sequence time-out feature are available when the external clock is in
use. Nor is the inter-segment dead time guaranteed.
5HFRUG
To select the desired number of samples for the single-shot
acquisition.
See Appendix A for model maximums.
*
External clock modes are available only if the EXT tr igger is not the
trigger source.
).
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1RWHVIRUXVLQJ([WHUQDO&ORFN
ger and the external
l
The time/div is expressed in s/div, to be understood to be samples/div.
À
À
The trigger delay is also expressed in samples and can be adjusted as normal.
À
No attempt is made to measure the time difference between the trig
clock. Therefore, successive acquisitions of the same signal can appear to jitter on the
screen.
À
The oscilloscope will require a number of pulses (typically 50) before it recognizes the
external clock signal. The acquisition is halted only when the trigger conditions have been
satisfied and the appropriate number of data points have been accumulated.
À
Any adjustment to the time/division knob automatically returns the oscilloscope to norma
(internal) clock operation.
²
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7LPHEDVH0RGHVDQG6HWXS
7,0(%$6(³6HTXHQFH — for operating in Sequence Mode
6DPSOLQJ
This menu is inactive when the external sample clock is being used.
Only single-shot acquisition is available (
6DPSOH&ORFN
For selecting a description of the signal applied to the EXT BNC
connector for the sample clock (
7–6).
see pages 7–6, 7–1).
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(NOT AVAILABLE WITH 9304C, 9310C, 9314C SERIES)
For combining or pairing channels to achieve more m emory and a
greater sampling rate by interleaving the ADCs in time. W hen “2” is
selected on two-channel models both channels are combined, or
paired. While when the same selection is made on four-channel
models either Channels 1 and 2 or 3 and 4 may be combined. But
when “1” on two-channel models or “4” on four-channel scopes is
selected, none of the channels is combined.
6HTXHQFH
When either “On” or “Wrap” are activated, the menu changes to the
one shown here. The associated m enu knob is us ed to choose the
desired number of segments, here given in example as “100
segments”..
Also, when “Sequence“ is “On”:
If the trigger mode is Single
the oscilloscope fills the segments
and stops.
But it will wait until
is pressed if there are not enough trigger
events to fill the segments.
If the trigger mode is Normal
the oscilloscope fills the s egments
and then, if more trigger events occur, the acquisition is restarted
from Segment 1.
²
Page 9
If the trigger mode is Auto
consecutive triggers exceeds a time-out that can be selected, the
acquisition is restarted from Segment 1. The tim e-out is selected in
“SPECIAL MODES” “UTILITIES”.
However, when “Wrap” is selected, the segments are filled
continuously until the STOP button is pressed. T he last
will be displayed. An alternative way to st op the W RAP sequence is
through AUTO mode; if the time between two consecutive triggers
exceeds a time-out that can be selected, the acquisition will stop.
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To select using the corresponding button or associated knob the
maximum record length for each segment.
and if the time between two
See Appendix A for
model maximums.
1RWH
A summary of the acquisition conditions is
displayed above the “TIMEBASE” menus, indicating
number of segments, available record length per segment,
sampling rate, and timebase setting.
n
segments
²
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