44
Subject to change without notice
C o n t r o l s a n d R e a d o u t
above the lowest graticule line to indicate the trigger time
position along the signal and thus can only be moved hori-
zontally.
FFT: DUAL, ADD and XY mode will not be offered in combina-
tion with FFT.
32.5 XY
In this mode CH1 will move the trace in X direction, hence the
readout will show ”CHX..“, CH2 will move the trace in Y direction,
hence ”CHY...“ will be shown rather than ”CH2...“.
As the time bases are not involved in XY no time base related
information will be shown. Also the trigger circuits are disabled
so no trigger information is shown either. The magnifier MAG
x10
29
is disabled. The ”0-Volt“ symbols will be shown as tri-
angles at the right hand graticule and above the sensitivities.
Both the HORIZONTAL
27
or the POSITION 1
13
knobs will
move the trace horizontally. The Y position is controlled by the
POSITION 2 knob.
32.5.1
Analog mode
The CH1 signal can not be inverted (if channel 1 was selected
for the X defl ection), there is hence no menu item in the CH1
menu (CH1 VAR pushbutton
31
). The TIME/DIV-SCALE-VAR
knob
28
is disabled.
Please note that the bandwidths and phase differences in XY
analog and digital mode differ considerably so there may be
changes in the signal display when switching the mode.
From serial number 049340007 (October 4th 2007), and fi rmware
version 05.300, a submenu is available for XY mode.
Pressing the “VERT/XY” pushbutton calls the “Vertical” menu
which contains the item “XY”. Pressing the “XY” function key
causes switchover to XY mode and simultaneously the display
of the “Vertical XY” submenu. It enables the selection of the
signal input (CH1 or AUX = AUXILIARY INPUT) to be used for X
defl ection, which is displayed in the menu under “X Channel”.
If CH1 is selected for X defl ection, “CH2” is automatically set as
the Y input which is displayed under “Y Channel”.
If “AUX” is chosen for X defl ection, “CH1”, “CH2” or “DUAL” (CH1
and CH2 simultaneously) can be used for Y defl ection.
32.5.2
Digital mode
The readout will indicate the sampling rate with which the A/D
converters digitise the input signals. The appropriate sampling
rate must be set depending on the signals and can be selected
with the TIME/DIV-SCALE-VAR knob, although the time bases
are disabled. With high sampling rates there may be gaps in
Lissajous representations. With too low sampling rates the
display may no longer allow you to determine the frequency
relationship of the signals.
It is recommended first to look at the signals in DUAL mode
and to set the sampling rate such that at least one signal period
will be displayed. Then XY should be selected. In XY digital mode
both channels may be inverted.
FFT: DUAL, ADD and XY mode will not be offered in combina-
tion with FFT.
33
CH2
/
VAR
(pushbutton)
This pushbutton opens the CH2 menu which offers the
following options:
33.1 AC DC
The pushbutton will alternate between AC and DC coupling.
The readout shows a ”~“ or ”=“ symbol after the sensitivity
indication.
33.1.1
DC coupling
The signal will be directly coupled to the input amplifier via
the BNC connector
35
and the input attenuator. The input
resistance of the scope is a constant 1 MΩ irrespective of the
sensitivity selected.
33.1.2
AC coupling
A capacitor is inserted between the BNC connector and the at-
tenuator, thus the DC content of the signal is blocked and a high
pass with a lower cut off frequency of approx. 2 Hz is created.
Low frequency signals will thus be more or less differentiated,
hence their shape and amplitude affected. If the DC content of
the signal changes, e.g. the duty cycle of pulses, the capacitor
must charge or discharge. This will cause a momentary Y shift
of the display.
33.1.3
50 Ω / 1 MΩ Input Impedance
This function allows you to select the input impedance of
channel 1. For measurement of low and high frequencies
voltages at sources with impedances deviating from 50 Ω, an
impedance setting of 1 MΩ is recommended, together with the
use of a frequency compensated divider probe for minimum
capacitive load.
If the source impedance is 50 Ω and the voltage to be measured
is within the voltage limits, a 50 Ω cable and 50 Ω impedance
setting should be used.
33.2 Ground (GND) On Off
The pushbutton will either connect the amplifier to the signal or
to ground. If set to Ground the readout will show a ground symbol
following the sensitivity setting where the coupling was indicated
before. In the Ground position and with automatic triggering a
trace will be visible, this is handy for setting the Y position of it
e.g. to the screen centre without disconnecting the signal. After
switching back to the signal, its amplitude can now be determined
with respect to the formerly set zero reference.
The 0 V (Ground) position can but must not be determined in
the way described above, as the readout shows a symbol ( )
VAR
VAR
VAR
x10
AUXILIARY INPUT
LC
0 ... LC3
LOGIC PROBE
Use recommended
probe only!
TRIG. EXT. / Z-INP.
LC/AUX
FFT
1M
Ω
II
15pF
max
100 Vp
INPUTS
1M
Ω
II15pF
max
250 Vp
X-INP
CH 1
VERT/XY
CH 2
HOR
MAG
CAT I
!
50
Ω
≤
5V RMS
50
Ω
≤
5V RMS
CH 1
CH 2
!
PROBE
ADJ
00
POWER
MENU
MENU
OFF
OFF
44
31
34
32
33
35
36
38
37
39
29
30
