OD1402 - Lesson 1/Learning Event 1
displaying only one trace. These are classified as single trace
oscilloscopes. They consist of one vertical amplifier and one
horizontal sweep generator connected to a cathode ray tube (CRT).
The oscilloscope (AN/USM 281C) used in this subcourse provides dual
trace operation. A dual trace oscilloscope has two vertical
amplifiers and two horizontal sweep generators. This provides dual
trace operation for the comparison of two electrical impulses at
the same time.
Sometimes, the recurring signal rate is so slow that it becomes
impossible to observe it on a conventional oscilloscope. Then, a
storage oscilloscope must be used. The storage oscilloscope is
designed to store the signal in its memory and then display the
signal on the CRT. In addition, the storage oscilloscope can be
operated as a conventional oscilloscope.
The AN/USM 281C oscilloscope (figure 1, on the next page) is a
lightweight, solid state instrument designed for general purpose
signal waveform measurements. It has single or dual trace
capabilities. The oscilloscope consists of the oscilloscope main
plugin unit. These units are described in the following
The main frame contains the CRT and power supply components and
provides three plugin compartments for the vertical amplifiers and
dual time base units. Of the three plugin compartments, the two
on the left are connected to the vertical deflection circuits. The
one on the right is connected to the horizontal deflection system.
Electronic switching between the vertical amplifiers allows a dual
trace vertical display.
The vertical amplifier is a wideband amplifier that provides
vertical deflection signals to the mainframe vertical amplifier
circuits. There are two vertical amplifier compartments in the
mainframe. This allows one amplifier to be used alone, for single
trace operation, or two amplifiers to be used for dual trace