Tektronix 5B12N, Instruction Manual

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Operating Instructions-5B 12N
Sweep Mode-Independent A or
B
Sweep Opera­
tion
Gen eral. The A and B buttons of the M O D E switch are
self-cancelling, and perm it independent operation of either
the A or B sweep_ Both buttons can be pushed in together,
permitting dual-sweep operation; this will be discussed later
under S we e p Mode - Dual-Sweep and D el ayed-Sweep
O peration_
Normal T ri g g e r ed Mode. The N ormal Triggered M ode
( AUTO T R IG button out) provides a repetitive triggered
display on either tim e base only when the corresponding
LEVEL control is correctly set and an adequate triggering
signal applied_ Otherwise , the sweep-generating circuits
remain
off
and there is
no
display_
Auto Mode and Bright Baseline. Operation in this mode
(AUTO TR IG button pushed in) provides a repetitive , trig­
gered display when the triggering signal is occurring at a
rate of 15 hertz or more and the L E V E L control is cor­
rectly set. When the trigger-repetition rate is l ess than about
15 hertz, or in the absence of an adequate triggering signal,
the sel ected sweep generator free runs at the sweep rate
selected by the SECO N DS/DIV switch to produce a
reference trace . When an adequate triggering signal is again
applied, the free-running condition ends and the sweep
generator is triggered to produce a stable display.
Sin gle Sweep
Mode (A Time Basel. When the A S I NGL
SWP button is pushed in, operation of the A sweep genera·
tor
circuits is simil ar to the normal m odes, except that only
one sweep can be produced until the sweep is m anually
reset. This mode can be used to photograph a non-repetitive
signal. Also, when the signal to be displayed is not repeti­
tive, or varies in amplitude, shape , or time, use of the Single
Sweep Mode eliminates the possibility of an unstable
presentation.
To use the Singl e Sweep Mode, first m ake sure the A
Tim e Base triggering circuits will respond to the event to be
displayed. Set
the A SIN G
L
SWP button for repetitive
sweep ( button out) and obtain the best possibl e triggered
display in the normal m anner (for random signals, set the A
LEV E L control so that the triggering circuit will respond to
a signal which is about the sam e am plitude as the random
signal). Then push in the A SIN GL SWP button and press
the R ESET button to arm the sweep_ This condition is
indicated by the R E A D Y l am p, which lights when the A
sweep generator is ready to accept a trigger_ The next trig­
ger pulse initiates the sweep, and a single trace will be
presented on the screen. The R E A D Y light goes out
im mediately upon receipt of the sweep-initiating trigger.
After the singl e sweep is terminated, the sweep generator is
"locked out" until again rese t. T o prepare the circuit for
another single-sweep display, press the R E S E T button
1-4
again. I n all modes, any sweep in process when the R E S E T
button i s pressed is terminated, allowing the system t o be
quickly reset.
Selectin g Sweep Rate. The A S E C O N DS/D I V switch
(dark gray knob) provides 21 calibrated A Time B ase sweep
rates ranging from one m icrosecond per division to five
seconds per division, and the B S E C O N DS/D I V switch
(light gray knob) provides 20 calibrated B Time B ase sweep
rates ranging from 0.2 m icrosecond per division to 0 . 5
second per division. The Variable control (red knob) is
associated with the A Time B ase. It provides continuously
variable sweep rates between the settings of the A
S E CO N DS/ D IV switch, and extends the sweep rate range to
about 12.5 seconds per division. The knob skirts of the A
and B switches are back-lighted to provide a direct readout
of both sweep rates.
Sweep Ma gn ification (A T i
m
e Base). The sweep m agni­
fier expands the A sweep ten times. The center one division
of the unm agnified display is the portion visibl e on the
screen when m agnified. Equivalent length of the magnified
sweep is about 100 divisions; any 10-division portion may
be viewed by adjusting the A POS I T I ON control to bring
the desired portion into the viewing area.
To use sweep magnification, first move the portion of
the displ ay which is to be expanded to the center of the
gra ticule. Then press the A SWP MAG button. The knob­
skirt readout changes by a factor of ten to provide a direct
readout of the m agnified sweep rate .
Sweep Calibration Check. The vertical and horizontal
deflection systems of the 5100-series oscilloscopes are gain­
standard ized to perm it a plug·in to be moved from one
oscilloscope to another (or from one compartment to
another within the oscilloscope) without the need to
recheck the calibration each time . H owever, the sweep
timing of both time bases can be checked and, if necessary,
adjusted
_
Sweep Mode-Dual-Sweep and Delayed Sweep
Operation
Gen eral. In addition to the independent A or B swe e p
operation discussed previously, the M O D E switch permits
simultaneous operation of both the A and B sweeps where
both are viewed simultaneously ( dual sweep). or where only
one is viewed, but is dependent upon the other ( A sweep
intensified by the B sweep, B sweep delayed, etc.).
Dual Sweep. Dual-sweep operation is attained by
pushing in both the A and B buttons of the mode switch. I n
this mode, the A sweep and the B sweep displays are viewed