Tektronix 549 Instruction Manual page 11

Operating instructions— Type 549
Line Voltage Selection
115 or 230 volt line voltage is selected by means of an
internal switch SW 602. Three voltage ranges, LO W 104/
208, MED 115/230 and HIG H 127/254 are selected by the
LIN E RANG E switch SW 602 on the back panel. The instru­
ment is normally shipped with these switches set for 115 V.
60
Line frequency is 50 to Hz.
C A U TIO N
Before applying power to the instrum ent, check
that the 1 1 5 V / 2 3 0 V
(located at the rear
c hassis) is positioned
source voltage.
FUNCTION OF CONTROLS
AND CONNECTORS
N O TE
The Tim e Base A and Tim e Base B controls serve
identical functions w ith
LE N G TH control.
TRIGGERING
LEVEL. Selects the amplitude point on the triggering signal
where sweep triggering occurs.
S TA B ILITY . Adjust the sweep triggering
stable display. The S T A B ILITY control can generally be set
to the PRESET position and left there. This PRESET position
with the LEVEL control midrange, provides stable triggering
for most displays.
MODE. A U TO position
signals with repetition rates higher than about 50 Hz. W ith
no trigger signal, or with a lower repetition rate, the time
base circuit free runs to provide a reference trace.
(triggered) position permits normal triggering on all trigger­
ing signals. No trace occurs when the triggering signal is
removed.
SLOPE. Determines whether the time base is triggered on
the negative (— ) or positive (+ ) going slope of the signal.
CO UPLING . AC position blocks the DC component of the
triggering signal and allows triggering to occur only on the
changing portion of the signal.
about 30 H z, use the DC position. AC LF REJ position attenu­
ates trigger signal frequencies below about 17 kHz, allowing
the trigger circuits to respond only to higher frequencies.
DC position permits triggering on both high and low (to DC)
frequency signals.
SOURCE. IN T NORM position uses a portion of the signal
applied to the vertical deflection plates of the CRT as a
trigger signal. IN T PLUG IN position applies to multitrace
plug-in units that provide a single-channel trigger signal
through pin 5 of the interconnecting plug (e.g. Tektronix
Type 1A1 plug-in unit). LIN E position uses a line-frequency
signal as a trigger. EX T position permits external triggering
on a signal applied to the TRIG G ER IN P U T connector.
Time Base Controls
TIM E/CM . Selects the time-base sweep rate.
2-2
in te rna l selector switch
o f the vertical am p lifier
correctly fo r the power
the exception o f the
circuits for a
permits normal triggering
TRIG
W ith frequencies below
VARIABLE (Time Base A). Provides an uncalibrated sweep
rate adjustment which w ill slow the sweep rate to at least
2.5 times the setting of the TIM E/C M switch. An U N C A LI­
BRATED lamp lights when the VARIABLE control is not in the
CAL position.
LEN G TH (Time Base B). Controls the length of the B sweep.
H O R IZ O N TA L DISPLAY. A.- Selects only Time Base A for
display on the CRT screen. B: Selects only Time Base B for
display on the CRT.
sweep functions. In this position a portion of Time Base B
is intensified during the time that Time Base A (the delayed
sweep) is in operation.
function. In this position, Time Base A is delayed at the
end of each delay period as determined by the B, TIM E/CM
AND DELAY TIM E switch setting and the D ELA Y-TIM E M U L TI­
PLIER 1:10 dial reading.
external signal to be applied to the horizontal deflection
circuit. Sensitivity is continuously variable with the VARIABLE
1-10 control.
READY Lamp. Lights when time-base circuit is ready for
triggering after being reset.
M AG NIFIER. Horizontally expands the portion of the sweep
in the center of the graticule by 5 times at any setting of
the TIM E/C M switch.
N O RM -SIN G LE SW EEP
position switch selects NORM AL or SIN G LE SW EEP operation
for either time base. Switch is spring loaded at the RESET
position. In the SIN G LE SW EEP position, selected time base
w ill sweep once upon receipt of trigger signal, then remain
inactive until the circuit has been reset with the RESET switch
or ERASE AND RESET button. Single sweep permits photo­
graphing or storage of nonrepetitive waveforms.
on
DELA Y-TIM E M ULTIPLIER 1-10. W orks in conjunction with
the Time Base B TIM E/C M AND DELAY TIM E switch. Varies
0
sweep delay from
Time Base B TIM E/C M AND DELAY TIM E switch.
H O R IZO N TA L P O SITIO N and FIN E. Positions the display
along the horizontal axis of the crt screen.
LOCATE button. When the Type 549 is operating as a
conventional oscilloscope, the LOCATE button provides a
trace finding mode. The gain of both the vertical and hori­
zontal amplifiers is reduced so that regardless of the input
signal, an on-screen display is presented. W ith either of the
STO RE buttons depressed the LOCATE button does
affect the horizontal or vertical gain, but the Horizontal
Amplifier is DC offset and moves the beam to the left of the
CRT screen. Th is places the beam in the locate zone of the
target (a non-store area) and permits vertical positioning
of the beam.
In either mode, the intensity is brought to a preset level
when the LOCATE button is depressed.
Other Controls
A M PLITUD E CALIBRATOR. Determines
voltage available at the CAL O U T connector.
5 mA Current Strap. Provides
square-wave current. The arrow indicates conventional cur­
rent (i.e. positive to negative).
B IN TE N BY A: One of the delayed-
A DLY'D: Another delayed-sweep
EXT I X and 1 0 X : Permits an
(Sweep mode selector).
10
to times the rate indicated by the
the peak-to-peak
a calibrated source
Three-
not
of
®T