Hameg CombiScope HM2008 Manual Download

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Subject to change without notice

10.4.3

Optimum display

In this display mode, so called “Alias“ signal display can be
avoided. The signals to be recorded are sampled with a higher
sampling rate than that required by the time coefﬁ cient and
the display resolution. This is enabled by the 2 M Byte storage
capacity per signal as it enables you to store more data than
actually required or displayable. As 2 M Byte data are available
although only 2000 can be displayed by the crt, one sample is
taken from 1000 to be displayed, the sample with the highest
deviation being taken. So each of the 2000 samples displayed
is taken out of 500 (2000 * 500= 1 M). This means, that in com-
parison with 2000 kByte memory and 2000 samples display,
signal frequencies can be 500 times higher before they could
cause aliasing. The minimum and maximum value display has
the disadvantage that more noise becomes visible. All samples
are displayed in vector mode as described in item 10.4.2.

STOP

Attention!

Due to “Optimal” display more noise becomes
visible as the minimum and maximum values are
displayed.

10.4.4

Status Acq. (acquisition)

In combination of AUTO, normal and single event capture, the
Pre Trigger time is displayed in % if the waiting time is higher
than 1 second. After 100% has been reached, the waiting time
for the trigger event is displayed. Due to the short pre trigger
time in small time deﬂ ection coefﬁ cient settings, only the waiting
time for the trigger event may become visible.

10.5 Self Cal

This function key leads to the submenu “Settings Self Cal“.
If the oscilloscope inputs are open (no inputs applied), an
automatic calibration (adjustment) can be made by pressing
“Start“. The calibration can be aborted by pressing the MENU
OFF pushbutton

The automatic calibration (adjustment) optimises the oscillo-
scope behaviour under the current temperature conditions,
after 30 minutes warm up time.

AUTOSET

(pushbutton)

Choosing AUTOSET will cause an automatic instrument setting,
dependent upon the actual input signal, which selects positions,
signal amplitude and time base for a reasonable display (in
FFT mode optimum parameter are set). The choice of analog
or digital mode will not be affected. In component test mode
(available only in analog mode), XY mode, or ADD; dual channel
mode will automatically be selected. If dual channel or CH1 or
CH2 were previously chosen this will remain. The digital modes
Roll, Envelope or Average will be changed to refresh mode.
AUTOSET will further set the intensity to an average value if it
was set too low. If a menu was opened it will be turned off by
AUTOSET. During the display of HELP texts AUTOSET is not

available. AUTOSET can and should be used during FFT ope-
ration to avoid misadjustment.

HELP

(pushbutton)

Pressing the HELP pushbutton will turn the signal display off
and display the help text. If a menu was opened, the help text will
refer to the menu, special menu or submenu option selected.
If a knob is moved another help text referring to this knob will
appear. Press HELP again to deactivate the text.

POSITION 1

(knob)

This knob can assume various functions which depend upon the
operating mode, the functions selected with the CH1/2–CUR-
SOR–MA/REF–ZOOM-pushbutton

and the menu option

selected.

13.1 Y Position

13.1.1

Y-Position of channel 1 (analog and digital mode)

POSITION 1 is for Y Position CH1 control, if Yt mode (time base
mode) is present and the CH1/2–CURSOR–MA/REF–ZOOM-
button

is not lit.

13.1.2

Y Position of the FFT display (only in digital mode) measu-

red with channel 1
Position 1 allows you to move the FFT spectrum display, the
FFT reference indicator (arrow symbol at the left side of the
graticule) and the FFT marker (X Symbol) in vertical direction.

13.1.3

Y position of reference signals (digital mode only)

The POSITION 1 control functions as the position control for
the signals stored in the reference memory if these conditions
are fulﬁlled:

A reference signal must be on display (SAVE/RECALL

Reference Display

(upper display area) REx (x = number of

memory location, select with INTENS)

On (with or without

associated settings).

After pressing the CH1/2–CURSOR–MA/REF–ZOOM push-

button

Math./Ref. was selected, the pushbutton will

light up green.

The POSITION 2 knob can also serve as a Y Position control
for signals stored in the reference memory, if the previously
mentiond conditions are met and ON is set in the lower sector
of “Reference Display“.

13.1.4

Mathematics Signal Position ( digital mode only)

The POSITION 1 control serves as a Y Position control for mathe-
matics signals, if after pressing the MATH pushbutton

(Mathe-

matics

Display (upper sector)) an equation (MA1...MA5) has been

C o n t r o l s a n d R e a d o u t

INTENS

HM2008

2 GSa

2 MB

200 MHz