Section IV Model 240A
Paragraphs 4-54 to 4-63
a sample of the RF voltage delivered at the output of seconds wide to the PIP MARKER AMPLITUDE con-
the buffer amplifier through the switch Mol. This trol, R117. The fall time in this circuit has been
switch is located inside the RF Unit and is driven by made sufficiently fast so that it will respond to
a mechanical linkage which is interlocked with the double pulsing from the two delay multi-vibrators
Crystal Selector Switch on the front panel. When the when the separation is greater than the width of the
crystal markers are turned OFF, the coaxial switch pulse.
is shorted so that no radio frequency voltage is
allowed to leak out of the RF Unit. 4-59. The output of the Pip Marker Generator is
fed to the Adder Amplifier, V205, by way of the RC
4-55. The output of the mixer section of V203 is fed network R230 and C238 to the plate of the tube. The
into RC networks which control the gain-versus- amplitude may be controlled by PIP MARKER AM-
bandwidth characteristics of the amplifier consisting PLITUDE control R117.
of the second section of V203. Additional bandwidth
control is obtained by means of the resonant cir-
cuits in the cathode of the second section of V203 4-60. COMPOSITE SIGNAL AMPLIFIER.
tuned by inductors L209 and L210. Additional con-
trol is obtained by means of the series resonant 4-61. Pip markers, generated in the Pip Marker
traps tuned by L204 and L205. The purpose of these Generator, are fed through the AMPLITUDE control,
bandwidth adjustments is to maintain an approxi- R117, and impressed on the plate-of tube V205. The
mately constant ratio of the passband of the am- birdie markers, derived from the Birdie Generator
plifier to the separation of the harmonics being ob- and associated switching, are fed to the #1 grid of the
served, so that the appearance of the birdie markers pentode section of V205.
on the screen will be uniform regardless of fre-
quency separation. 4-62. The detected output of the system under test
is connected to J203 TEST SIGNAL IN. This signal
4-56. PIP MARKER GENERATOR. passes through the TEST SIGNAL IN-AMPLITUDE
CONTROL, R234, and drives the grid of the triode
4-57. A trigger spike is derived from the multi- section of V205, whose plate is common to the pen-
vibrator tube, V501, and is fed to two separate de- tode section. The composite signal, thus derived, is
lay multi-vibrators, VlOl and V102, by way of fed to the COMPOSITE SIGNAL OUT jack, J201, and
capacitors C103 and C108. These two delay multi- to the CALIBRATE jack for use with headphones or
vibrator circuits are identical and are controlled by an oscilloscope.
R107 rind R119, labeled PIP MARKER POSITION #1
and #2. These controls are identical in function and
COMPOSITE
may be used interchangeably regardless of the SIGNAL OUT
sequential numbering. PIPS IN
FROM VI03 CALIBRATE
BIRDIES
IN FROM TEST SIQNAL IN
J203
# v205' + L) TEST AMPLITUDE
- P
U Figure 4-11. Composite Signal Amplifier
vsol I rn I
I
VI02 4-63. POWER SUPPLY.
Figure 4-10. Pip Markers - Block Diagram 4-64. The Power Supply of the Sweep Signal Genera-
tor is manufactured for either the Model 240A,
60 cps at 105 to 125 volts, or the Model 240AP, 50 cps
at 105 to 125 volts. Operation on any other voltage
4-58. The function of the multi-vibrators is to gen- or frequency will result in serious damage to the in-
erate two new trigger pulses having adjustable de- strument.
lays with respect to the trigger derived from the
multi-vibrator which drives the sweep system. 4-65. All power is fused by the front panel FUSE,
These two trigger pulses are capacitively coupled F601, which is contained in a replaceable type cart-
through C102 and C107 to the diodes CR102 and ridge mounted on the front panel adjacent 40 the pilot
CR103 into the common plate connection on the light. A voltage stabilizer, T602, is connected to:
actual pip generator tube, V103. This tube pro- (a) a regulated negative supply consisting of the
duces a narrow spike approximately 50 micro- diode rectifier CR601 and the glow regulator type
4 -6 |
ACEC
HEWLETT-PACKARD
