Model 130B Sect.111 Page 1
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SECTION 111
THEORY OF OPERATION
3-1 GENERAL CONTENT In addition to forming the 'internal sweep of the
This section contains a brief description of the oscilloscope, the Sweep Generator also supplies
the required unblanking pulse which brightens the
over-all operation of the Model 130B Oscilloscope, trace during each sweep.
description of each major section and detailed
description of a Schmitt trigger.
D. CALIBRATOR
An internal square-wave calibrator, with a
3-2 OVER-ALL OPERATION nominal frequency of 300 cps, is provided for set-
The block diagram in Figure 3-1 shows the basic ting the basic gain of the amplifiers. Turning
either the VERT. or HORIZ. SENSITIVITY switches
circuits of the Model 130B Oscilloscope. to CAL., turns on the calibrator supply voltage
and connects its output to the appropriate amplifier.
A. VERTICAL AMPLIFIER
The Vertical Amplifier receives the input E. CATHODE RAY TUBE
signal, amplifies it, and drives the vertical deflec-
tion plates of the cathode ray tube. In addition, The cathode ray tube is a SAQP - mono-
this amplifier determines the vertical position of accelerator type. It is normally supplied with a
P1 phosphor screen but is available in the P7 and
the spot on the screen and supplies a signal for syn- P11 phosphors also and P2 upon special order.
chronizing the sweep with the vertical input signal. All are electrically interchangeable and the tube is
easily changed. The mono-accelerator anode
makes possible a simple astigmatism adjustment
B. HORIZONTAL AMPLIFIER which requires no resetting when adjusting the
FOCUS or INTENSITY controls. The deflection
The Horizontal Amplifier receives its signal plate terminals are connected through removable
either from the horizontal INPUT jack or from the jumpers at the rear of the instrument so that di-
Sweep Generator, amplifies it and drives the hori-
zontal deflection plates of the cathode ray tube. rect connections to the plates can be made easily.
Except for the provisions in the Horizontal Ampli-
fier for amplifying the internally- generated saw-
tooth voltage, it is essentially the same as the 3-3 VERTICAL AMPLIFICATION CHANNEL
Vertical Amplifier.
The vertical amplification channel consists of
three parts: the AC-DC switch, the input attenu-
SflEEPGENERATOR ator,and the amplifier section proper.
The Sweep Generator forms a sawtooth volt-
to control the horizontal movement of the spot
A. AC - DC SWITCH
across the face of the cathode ray tube. The Sweep
Generator is divided into two parts: 1) a sawtooth The signal comes into the input terminals and
generator, 2) a trigger generator, which starts is fed to the AC-DC switch. For ac coupling, a
the sawtooth. The trigger generator controls capacitor is switched into the signal path. In the
allow the operator to choose the point at which the DC position, the signal goes directly to the input
sawtooth sweep begins. attenuator. |
ACEC
HEWLETT-PACKARD
