BK Precision 5105B, Instruction Manual, Page: 35 / 48

35
Subject to change without notice
HORIZONTAL
CH CH
TIME / DIV
SCALE
·
VAR
X-POS
MODE
FILTER
SOURCE
TRIG ’ d
NORM
HOLD OFF
LOGIC
TRIGGER
LEVEL A/B
50s 5ns
DELAY
CH 3/4 HOR MAG
VAR
x10
POWER
20
19
26
27
23
25
21
28
24
22
29
30
as the automatic start will have occurred before the signal
arrived. Automatic triggering is possible with or without peak
detection. The LEVEL A/B
control will be active in both
modes.
In peak detection mode the range of the level control is limited
to the peak-to-peak voltage of the signal. Without peak
detection any level can be set. If the trigger level is set such
that no triggers are generated the automatic triggering will
nevertheless start the time base. The signal will thus remain
visible but will be untriggered.
Whether peak detection is active or not depends on the mode
and the settings in ”FILTER“ (trigger coupling). The mode active
will be shown by the behaviour of the trigger point symbol when
turning the LEVEL knob.
20.2. Normal (trigger)
If the NORM-LED lights up normal triggering was selected.
In normal trigger mode both the peak detection and the
automatic time base start will be disabled. Hence if there is
no sufficient trigger signal the screen will remain dark in ana-
log mode. In DSO mode signal capturing will also stop unless
the roll mode was selected.
In this mode there is no lower frequency limit for signals.
20.3 Single (sweep/capture)
In single sweep/capture mode the time base selected will
accept only one trigger for one sweep/capture after it was
armed. The NORM-LED will light up, Auto triggering is
disabled.
For further information about the precise operation see RUN/
STOP pushbutton
description.
FILTER (pushbutton)
After this pushbutton is depressed it will depend on the
settings chosen in MODE
(Edge, Video, Logic) which menu
will be offered. In XY mode the pushbuttons: MODE , FIL-
TER and SOURCE are disabled as XY displays can not
be triggered.
21.1 Menu: Slope
The menu ”Edge“ will appear if ”Edge“ was selected in the
”Trigger“ menu to be called with MODE
pushbutton and
after the FILTER pushbutton was depressed. For further
information see ”Trigger coupling“ (Menu ”FILTER“) under the
heading ”Triggering and time bases“ and the instrument
specifications. The following settings are available:
21.1.1 Trig. Filter
– AC: The trigger signal is AC coupled via a large capacitor
in order to reach a low cut-off frequency.
Readout: ”Tr:Source, Slope, AC“
– DC: The trigger signal is DC coupled. No peak triggering
is possible.
Readout: ”Tr: Source, Slope, DC“
– HF: AC coupling with a small capacitor suppressing low
frequency signals. Hence the signal display and the trigger
signal derived are not any more identical, the trigger point
symbol will be ”parked“ in DSO mode and will not react to the
LEVEL A/B
control. In analog mode the trigger point symbol
is switched off. As a combination of HF coupling and LF or
Noise Reject is not meaningful both menu options will not be
shown.
Readout: ”Tr:Source, Slope, HF“.
– LF: The trigger signal is sent through a low pass in order
to suppress high frequency components. As this will
already suppress hf the noise rejection mode will be set to
OFF automatically.
Readout: ”Tr:Source, Slope, AC or DC, LF“.
– Noise Reject: Noise rejection (reduction) means a reduced
trigger amplifier bandwidth and consequently less trigger
signal noise.
Readout: ”Tr:Source, Slope, AC or DC, NR“.
21.1.2 Slope
”SLOPE“ determines whether the rising or falling portion of a
signal shall trigger, the level is set with the LEVEL A/B
control.
In ”Both mode“ both slopes will trigger, this is also true in
single sweep mode. This allows e.g. the display of eye
diagrams.
21.2 Menu: Video
In order to reach the menu ”Video“ proceed as follows:
Press MODE
to open the ”Trigger“ menu, select ”Video“,
then press the FILTER pushbutton. Further information
can be found under ”Video“ (tv signal triggering) in the chapter
”Triggering and time bases“ and in the instrument specifica-
tions. The following settings are available:
21.2.1 Frame, Line.
Depending on the setting chosen triggering will be on frame
or line sync pulses. The selection will also affect other menu
items.
Readout: ”Tr:Source, TV“.
21.2.1.1 Frame
– ALL: In this mode the sync pulses of each half frame can
trigger.
– Even: In this mode only the sync pulses of even half frames
can trigger.
– Odd: In this mode only the sync pulses of odd half frames
can trigger.
21.2.1.2 Line.
- All: In this mode all line sync pulses can trigger.
- Line No: The line number with its line pulse that is used
for triggering can be selected with the INTENS knob .
- Line min: One pushbutton operation will be sufficient to
switch back to the lowest possible line number.
C o n t r o l s a n d R e a d o u t