20
Subject to change without notice
coefficient switch to time vernier (fine adjustment)
control and vice versa.
The current function is indicated by the VAR LED. The
TIME/DIV
. knob functions as a vernier when the VAR LED
is switched on, but the time base setting remains
calibrated until the (vernier) knob is operated. The readout
now indicates e.g.
”>10ms”
instead of ”10ms”. Rotating
further anticlockwise increases the time deflection
coefficient (uncalibrated) until the maximum is reached
indicated by a beep. Rotating the knob clockwise has the
opposite effect. Now, the vernier is again in the calibrated
position and the symbol
” >”
extinguishes.
Underneath the front panel sector described above,
the BNC sockets and two pushbuttons are located.
(25) INPUT CH I (X)
BNC socket.
This BNC socket is the signal input for channel I. The outer
(ground) connection is galvanically connected to the
instrument ground and consequently to the safety earth
contact of the line/mains plug. The
AC/DC/GND
pushbutton
(26) is assigned to the input.
In
XY
mode, signals at this input are used for the
X
deflection.
(26) AC/DC/GND x1/x10
Pushbutton with several functions.
AC/DC/GND:
Briefly pressing this pushbutton opens the input coupling
pulldown menu if a channel mode is present in which
channel I is activated.
The following input couplings are available:
AC
,
DC
and
GND
(ground). Please note “B: Menu Display and
Operation”.
After the pulldown menu has extinguished, the READOUT
displays the present input coupling at the bottom right
hand of
”Y1: deflection coefficient”
; the “
~
“ symbol
indicates AC, the “=” symbol DC and “GND” is for ground.
The
GND
setting disables the input signal and the
VOLTS/
DIV (14)
knob. Then in automatic trigger mode (Yt) the
undeflected trace is visible representing the 0 Volt trace
position; in XY mode the X deflection is deactivated.
x1/x10:
Probe factor selection is performed by pressing and
holding the pushbutton. This selects the indicated
deflection coefficient of channel I displayed in the
Controls and readout
Functions
“sea”:
In “sea” (SEARCH) mode, the hold off time is automatically
set to minimum and for the first few divisions the trace is
blanked. The point at which the trace is unblanked can be
varied with the DEL/TR. POS. (21) control (fine adjustment)
from about 2 to 7 divisions. The blanked section serves as a
guide to the delay time. The delay time is based on the current
time deflection coefficient setting and can also be coarsely
set with the
TIME/DIV
control (range: 20ms to 100ns).
The signal position at which the unblanking occurs marks
the trace start position that is present after switching over
from “sea” to “del”. This enables lower time deflection
coefficient settings for signal expansion.
“del”:
In “del” (DELAY) mode, a trigger event does not start the
trace at once but only initiates the delay time. After the
delay time has elapsed the trace is started. Selecting lower
time deflection coefficients (higher time base speed)
causes a signal expansion in X direction.
The
DEL/TR. POS.
(21) control can still be used for
correcting the signal start position affected by the TIME/
DIV setting.
Note: With higher expansion rates the trace intensity may
reduce drastically.
“dTr”:
In “dTr” (triggered DELAY) mode the first trigger unit, used
for triggering in undelayed time base mode, starts the
delay time as in “del” mode. After the delay time has
elapsed the delay time base must be triggered by the
second trigger unit, to start and unblank the trace. The
latter requires suitable instrument settings (
LEVEL, SLOPE
)
to enable triggering.
Note: The trigger indicator LED (TR) (10) only indicates the
trigger condition of the first trigger unit. It may be lit although
the trigger conditions for the second time base are not
met and the trace remains blanked.
As in “del” mode the
DEL/TR. POS
..... (21) control can still be
used. In contrast to complex signals the effect of this function
may not be noticed with simple repetitive signals as the trigger
point ‘hops’ from cycle to cycle, each being the same.
(24) Z ON/OFF VAR
. Pushbutton with two functions.
The functions are available only in analog mode!
Z ON/OFF:
Briefly pressing the pushbutton switches over the function
of the TRIG. EXT. (30) BNC socket from external trigger
input to intensity modulation input and vice versa. In
connection with external triggering, delay time base (“sea”,
“del” or “dTr”) and “Component Tester” mode, Z
modulation can not be enabled.
Z modulation is shown on the READOUT to the right of
“trigger source, slope and coupling” indicated by the letter
“Z”. High TTL level (positive logic) gives blanking, dark,
low level gives unblanking, bright. No higher voltages than
+5 Volt are permitted.
VAR.:
Pressing and holding the button changes the function
of the
TIME/DIV.
(22) knob from time deflection
