20
Horizontal System
the maximum amount of data. Each column in the signal
window displays up to 40 detected data values (limited
by processor performance). How much data is currently
displayed depends on the displayed time window and the
current sampling rate. If peak detection is activated, each
column displays up to 20 pairs of min/max values. The
memory depth always corresponds to the maximum ac-
quisition memory. The displayed sampling rate is identical
with the current sampling rate. Peak detection is used if
the displayed time window contains more data than 40 *
signal window columns in the acquisition memory or min/
max data in the acquisition memory.
5 .3 .6 .3 AUTOMATIK
This function is the default setting and offers the best
compromise between maximum repeat rate and maximum
sampling rate (selection of memory depth). Each column
in the signal window displays up to 10 captured data va-
lues. How much data is currently displayed depends on
the displayed time window and the current sampling rate.
When peak detection is activated, each column displays
up to 5 pairs of min/max values. The memory depth is at
least twice as much as the storage capacity set for the
maximum repeat rate (limited by the maximum acquisition
Fig. 5.3: Example figure of AM modulated signal with max. sampling rate
memory). The displayed sampling rate corresponds to the
current sampling rate divided by the amount of data skip-
ped while loading from the acquisition memory. If peak
detection is activated, the displayed sampling rate corres-
ponds to the current sampling rate.
All settings apply the identical current sampling rate
(sampling rate used to write to the acquisition memory).
In STOP mode it is also possible to change menu items.
This does not impact the current memory depth but the
amount of displayed data will be adjusted. Peak detection
is also activated in STOP mode (time base in microse-
conds). In time bases displaying each sampling point, all
three settings behave identically (except used memory
depth and signal update rate). Table 5.1 displays advan-
tages and disadvantages of each setting. Finally, it needs
to be mentioned that this menu replaces the adjustable
memory depth, a standard for other manufacturers. An
adjustable
memory depth is intended to allow users to
understand the relation between memory depth, time
base and sampling rate and to evaluate advantages and
disadvantages. With this option, the oscilloscope always
captures signals with the maximum sampling rate. This al-
lows users in STOP mode to zoom in retrospectively, even
at the maximum repeat rate. It is also possible to zoom out
at the maximum repeat rate if the STOP mode was run at
fast time bases. If a high repeat rate can only be attained
Fig. 5.4: Example figure of AM modulated signal with automatic setting
Setting
Advantages
Disadvantages
Application
Maximum waveform rate:
ı
Many captures in one image
ı
Rare events can be detected more
quickly in connection with per-
sistence
ı
Quick response to Operation or
change in signal
ı
Low noise band
ı
High aliasing risk
ı
Low accuracy of details
ı
Low accuracy of measurements
due to reduced amount of data
ı
Search for rare events
ı
Displaying modulated signals
Maximum sample rate
ı
Maximum accuracy of details
ı
Lowest aliasing risk
ı
High accuracy of measurements
ı
Slow response to operation or
change in signal
ı
Low signal update rate
ı
Higher visibility of noise
ı
For signals with high frequency
parts
ı
Assessment of small signal
details
Automatikc:
ı
Average signal update rate
ı
Reasonably smooth operation
ı
Good accuracy of measurements
ı
Low noise band
ı
Possible aliasing
ı
Default application
Table 5.1: Advantages and disadvantages of each setting.
The entire oscilloscope memory can only be read out in STOP
mode if the maximum sampling rate has been activated.
