HP 415E User Manual

Model 415Е
Section IV
Paragraphs 4-1 to 4-4
SECTION ІМ
PRINCIPLES OF OPERATION
4-1. GENERAL.
4-2 The 415E is a high-gain tuned amplifier which
takesan input froma bolometer, crystal, or any audio
Source, amplifies itandapplies ittoa meter calibrated
for use with square-law detectors. With bolometer
or biased crystal operation, the Model 415E supplies
the appropriate bias current. Figure 4-1 is a block
diagram which illustrates instrumentoperation. Refer
also tothe schematic diagrams, Figures 5-11and 5-12
which fold out of the manual for easy reference.
St ATTEN INPUT
RANGE AMPLIFIER
А251 A3QI-Q4
INPUT
TRANS
TI
COARSE
GAIN
CONTROL
FINE 27 ATTEN and EXPAND
GAIN RANGE AMPLIFIER ATTEN
CONTROL A2SI АЗ05-06 А252
4-3. INPUT CIRCUITS.
4-4. Тһе input voltage is first routed through INPUT
Switch, A1S1. In the HIGH position it is applieddirec-
tly
to
the
first
section
of
the
range
attenuator,
A2S1.
Whenthe INPUT switch is set to any other position but
HIGH, the input signal passes through transformer T1
whose turns ratio provides a 50 to 1 impedance trans-
formation, converting a 50 to 200 ohm source to 2500
to 10,000 ohms (which is the range of best noise figure
for the INPUT AMPLIFIER).
EXPAND
NOTES
DARK LINES REPRESENT AC SIGNALS
FLOW PATH WHILE LIGHT GRAY LINES
REPRESENT DC SUPPLY AND SIGNAL
FLOW PATH
Figure 4-1.
02152-1
FINAL
AMPLIFIER
A3QIO-13
AMPLIFIER
A3Q8/Q9
TUNED
AMPLIFIER
AMPLIFIER Азат.
OUTPUT я
© [FRED]
«вано
Block Diagram

HP 415E Specifications

General

Brand	HP
Model	415E
Category	Measuring Instruments
Language	English