I Model 166D, Mx-2962/USM-l05A Section I11
Paragraphs 4-1 to 4-2
SECTION IV
PRINCIPLES OF OPERATION
4 -1. 0 VER ALL FUN CTI 0 N A 1 DES CR I PTlO N a. AMPLIFIER AND TRIGGER GENERATOR. -
The input or. reference trigger is applied to one grid
The Model 166D provides the @I Model 160B and of amplifier V1, a differential amplifier, and a dc
170A Oscilloscopes with delayed sweep operation. signal from the TRIGGER LEVEL control is applied
The unit inserts a known amount of delay, which cari to the other grid. The output of the amplifier is a
be selected at the front panel, between a reference single-ended' signal which is proportional to the instan-
trigger and the start of the main sweep generated by taneous difference between the trigger and dc signals.
the oscilloscope. The Model 166D itself consists of As shown in the figure, the TRIGGER SLOPE switch
a sweep generator and a delayed-trigger generator reverses the trigger and dc signals when switched
as shown in figure 4-1. The sweep generator gen- from one polarity position to the other. The switch
erates a linear voltage ramp, the delaying sweep, thereby determines the phase between the trigger
which is applied to the delayed-trigger generator. signal and the output of the amplifier. With the switch
The delayed-trigger generator generates a trigger set to +. theoutput ofamplifiCrV1 is 1800 out of phase
at the end of the delay period selected at the front, with the trigger signal; with the switch set to -, the
panel and delivers the trigger to the main sweep gen- output of the amplifier is in phase with the trigger
erator of the oscilloscope, which then provides the signal.
delayed sweep.
4-2. SWEEP GENERATOR. The output of amplifier V1 must be negative-going
an& must cross the +llO-volt level to start a sweep.
A block diagram of the delaying sweep generator is Since the output of the amplifier is proportional to the
shown in figure 4-2. In addition to the actual sweep difference between the trigger signal and the dc value
generating circuits (V5, 7, 9, 10, and 13) the sweep selected by the TRIGGER LEVEL control, the point
generator contains amplifying and shaping circuits on the trigger signal at which the amplifier output is
(VI and 4) and gating circuits(V8). The amplifying +110 volts depends upon the setting of the control.
and shaping circuits provide adequate triggering of Thus the TRIGGER LEVEL control permits selection
the sweep circuits, and the gating circuits provide of the voltage level which the trigger signal must cross
unblanking to the crt. to start a sweep.
0 ITRIGGER SOURCE 1
/
!.
TRIGGER SIGNAL DELAYED
TRIGGER
G EN ERATOR GENERATOR
I
I. \\
. \ \ b I SWEEP MODE 1
I \\
! I DELAYING SWEEP 1
', b
\
I
0 I SWEEP SELECTOR 1
I
I
Figure 4-1. Overall Block Diagram
01227-1 4- 1 |
ACEC
