Tektronix 570, Руководство пользователя

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SECTION 3
CIRCUIT DESCRIPTION
BLOCK DIAGRAM
General
The Block Diagram shows interconnections
of the functional parts of the instrument , except
for the power suppli e s . Functions of the switches
are shown instead of their actual connections.
Step Generator
The Step Generator receives the line frequency
w aveform, shifts the phase and shapes it to
provide a current pulse of a fixed amplitude .
The current pulses which are either 1 20 or
240 pulses per second , depending upon the setting
of the STEPS/SEC Control, are fed to a Miller
integrator.
The Miller integrator converts the current
s teps to a series of voltage steps , a staircase
waveform.
Step Amplifier
The positive-going waveform from the Step
G enerator is amplified and inverted by the step
amplifier for application to the device under
test. Any current drawn from this amplifier
by the device under test is measured by the
V ertical Amplifier in the GRID position of the
P L ATE-SCREEN-GRID Control.
+ D C Circuit (Floating Power Supply)
The + DC Circuit provides a variable regulated
voltage for application to the device under test.
C urrent drawn from this Circuit is measured
by the Vertical Amplfier in the SCREEN position
of the P L ATE-SCREEN-GRID Control.
Plate-Sweep Generator
The Plate-Sweep Generator rectifies the
transformer waveform to provide positive­
going sweeps of plate voltage. Current drawn
from this circuit is measured by the Vertical
Amplifier in the PLATE position of the PLA TE­
S C R E E N -GRID Control. The SERIES LOAD
Control selects the series resistance for the
P late-Sweep Generator.
Horizontal Amplifier
The PLATE-GRID Control connects the grid
o r plate of the device under test to the Horizontal
Amplifier. The Horizontal Amplifier amplifies
the signal and converts it for push - pull appli­
c ation to the deflection plates .
Vertical A m p lifier
The Vertical Amplifier amplifies the signal
s elected by the PLA TE-SCREEN-GRID Control
and applies it to the vertical deflection plates.
For a more complete diagram of the PLA TE­
S C R E E N -GRID Control see the CRT Display
Switching diagram.
STEP G E N ERA TOR DIAGRAM
Split-load Phase I nverters
The main power transform e r , T40 1 , supplies
35 volts at line frequency to the phas e - shifting
networks , R6 , C6 and R35 , C35. PHASE ADJ
A has a small range of adjustment to permit
this circuit to be adjusted to coincide with the
phase of the Plate- Sweep Generator waveform.
P H A S E ADJ B has additional range to permit
its output to be set at 90 degrees with respect
to the A circuit. V8A and V38A are Split­
Load Phase Inverters with equal resistance
in the plate and cathode circuits. The wave­
form at the plate is 180 degrees out of phase
at the cathode.
The dc component of the
waveform is blocked by coupling capacitors ,
C 8 , C I O , C38 and C40; and the waveform is
rectified by full-wave rectifiers.
Shaper A m p l i fiers
The output from each pair of rectifiers is
applied to a pentode amplifier. The rectifier
output is a negative-going rectified sine wave
of sufficient amplitude to hold the pentodes
cut off except for short pulses as the grids
approach ground potential. Since the pen-
AA
Circuit Description - Type 570
3 - 1