Lesson 3/Learning Event 7
Learning Event 7: TEKTRONIX OSCILLOSCOPE AN/USM-281C.
The Oscilloscope 281C, shown in figure 6, is designed for general
purpose wave form measurements using a single or dual-trace display with
normal or delay sweep.
It consists of Oscilloscope OS-245(P) /U (main
frame); two vertical amplifier plug-in units, AM-6565/U; and Dual Time Base
Plug-In Unit TC-1085/U.
a. Main frame. The main frame contains the display (Cathode Ray Tube
(CRT)), power supply components and three compartments for provisions to
plug in the two vertical amplifiers and time base units.
The main frame
compartments are compatible with other plug-in units which are not supplied
with the oscilloscope.
b. Vertical amplifier. The vertical amplifiers are wideband amplifiers
(DC to 50 MHz) that provides vertical deflection signals to the mainframe
vertical amplifier circuits. Constant bandwidth is provided over all of the
deflection factor settings with each setting selectable for either
calibrated or uncalibrated operation. Display polarity is also selectable,
as is the magnification factor. Use of two vertical amplifier compartments
in the main frame allows one amplifier to be used alone for single-trace
operation or two amplifiers to be used for dual-trace operation.
The
vertical amplifier can also be used in the mainframe horizontal axis
compartment for calibrated X-Y display purposes.
c. Dual time base.
The dual time base unit provides horizontal
deflection signals to the main frame CRT circuits for Normal, Intensified
Delaying, Delayed and Amplifier modes.
Either calibrated or uncalibrated
operation may be selected in any mode. In normal sweep mode, only the main
sweep operates.
In intensified delaying sweep mode, the main sweep is
intensified only during the periods set for the delayed sweep with the
position of the intensified portion adjustable to any point of the main
sweep. In delayed sweep mode, the intensified portion of the main sweep is
displayed over the full 10 centimeters (CRT) of the graticule area.
In
amplifier mode, the horizontal amplifier can be used for X-Y displays or for
an externally applied sweep signal.
d. The description of the controls, indicators, and connectors for this
oscilloscope are explained in table 7 of the annex.
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