44
Subject to change without notice
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: XY mode will not be offered in combination with FFT.
32.6 Bandwidth Full
/
20 MHz
This pushbutton will select full or 20 MHz bandwidth.
–
Full:
Full bandwidth will be the one given in the specifications.
–
20 MHz:
Provided measuring modes allow full bandwidth. This can
be reduced to 20 MHz (–3 dB) in order to attenuate high
frequency noise e.g. The readout will show BWL = bandwidth
limited. The bandwidth limitation affects both channels and
pertains to analog and digital mode. In XY digital mode the
limitation is equal to Yt mode. In XY analog mode the limi-
tation affects only CH2.
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.
33.2 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 ( )
for 0 V which is displayed 4 mm right of the vertical graticule
line in the screen center.
33.3 Invert On Off
The pushbutton will alternate between not inverted and inverted.
An inverted signal will be indicated in the readout by a bar above
the channel symbol. The trigger signal taken from an input will
not be affected.
33.4 Probe
The menu display depends on whether a probe with automatic
dividing factor identifi cation is connected or not. The actual
current parameter are taken into account at the display of
voltage measurement.
33.4.1
If a HAMEG probe with automatic identifi cation is connec-
ted, the readout shows “Probe“ in normal intensity and below
the dividing factor (e.g. *10).
33.4.2
If the “CH2“ menu is called, “Probe“, the last set dividing
factor and the INTENS knob symbol are displayed if a probe wit-
hout identifi cation is connected. Pressing the allocated function
key cause “Probe“ to be displayed with higher intensity and the
FOCUS TRACE MENU pushbutton
3
constantly lit. Then the
INTENS knob
2
can be used to select a dividing factor which
should accord with the connected probe.
33.5 Variable On Off
On condition “On“ the CH2 VAR pushbutton
33
light. Then the
VOLTS/DIV–SCALE–VAR knob
17
CH2 serves as variable control
that enables to change the defl ection coeffi cient continuously
over the complete range and consequently the signal display
height. If uncalibrated a “
>
“ sign is displayed by the readout
in front of the defl ection coeffi cient; calibrated a “:“ sign. The
results of voltage measurement are labelled in the same way.
After switching over from “Variable on“ to “Variable off“ with
the function key, the VOLTS/DIV–SCALE–VAR knob
17
returns
to 1-2-5 sequence switching and CH2 to calibrated condition.
34
INPUT CH1
(BNC connector)
This is the CH1 signal input connector. In Yt mode it is a Y input,
in XY mode it is the X signal input. The connector housing is con-
nected to the instrument housing and thus to safety ground. The
ring around the connector is the probe identifi cation contact,
no voltage may be applied here.
C o n t r o l s a n d R e a d o u t
AUXILIARY INPUT
TRIGGER
EXTERN
Z-INPUT
AUX
1M
Ω
II
15pF
max
100 Vp
INPUTS
1M
Ω
II15pF
max
400 Vp
CAT I
!
CAT I
!
VERT/XY
CH 1
VAR
CH 2
VAR
HOR
VAR
MAG
x10
FFT
CH 1
CH 2
X-INP
POWER
43
31
34
32
33
35
36
37
38
29
30
