Agilent Technologies 300A User manual

Errata
Title & Document Type: 300A Harmonic Wave Analyzer
Manual Part Number: N/A
Revision Date: 11/30/1955
HP References in this Manual
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Hewlett-Packard's former test and measurement, semiconductor products and chemical
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this manual copy. The HP XXXX referred to in this document is now the Agilent XXXX.
For example, model number HP8648A is now model number Agilent 8648A.
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t
OPERATING MANUAL
PLUS
SERVICE MANUAL
MODEL 300A
HARMONIC WAVE
ANALYZER
This is a combined Operation, Instruction, and Service
Manual for all ~ Mode1300A Harmonic Wave Analyzers.
This manual contains complete operation and servicing
instructions for the 300A and may be used in place of
thl~ Instruction and Operating Manual originally supplied
with each ins trument.
Copyright 1956 by Hewlett-Packard Company
The information contained in this booklet
is intended for the operation and main-
tenance of Hewlett-Packard equipment and
is not to be used otherwise or reproduced
without the written consent of the Hewlett-
Packard Company.
HEWLETT-PACKARD COMPANY
PAGE MILL ROAD, PALO ALTO, CALIFORNIA, U.S.A.

II
MODEL 300A HARMONIC WAVE ANALYZER
INSTRUCTION & OPERATING MANUAL
TABLE OF CONTENTS
SECTION I
GENERAL
Page
1-1
1-2
GENERAL DESCRIPTION
SPECIFICATIONS • • • · . . . · . · .
· .
III
III
SECTION II
OPERATING INSTRUCTIONS
2 -1 23D VOLT OPERATION.
·· · ····· · · · •
III
2 -2
CONTROLS & TERMINALS
· · · ··· · · · · •
IV
2 -3
OPERATION.
. . . .· · ·· · · · · · · • • · · · · ·
IV
2-4
CALIBRATION ADJUSTMENT PROCEDURE.
···• •
IV
2 -5
MEASUREMENT PROCEDURE.
· · · · · •···
IV
2 -6
MEASUREMENT PRECAUTIONS.
·· · · · · · · · •V
2-7 SELECTIVITY.
. . .· · · · · · · · · · •V
SECTION III
CIRCUIT DESCRIPTION
3-1 GENERAL ••••
·.. . . . .. . . .... . .
SECTION IV
MAINTENANCE
VI
4-1
CABINET REMOVAL.
· · · · · ·· · · •· · •··
VII
4-2
TUBE REPLACEMENT.
··········•·•·•·
VII
4-3
LOCAL OSCILLATOR AMPLITUDE ADJUSTMENT.
•·
VII
4-4
VOLTAGE REGULATOR ADJUSTMENT.
· · • • • ·•·•
VII
4-5
HUM BALANCE ADJUSTMENT.
· · •·••••••••·
VII
4-6
BALANCED MODULATOR ADJUSTMENT.
•· · • • ·
VII
4-7
SELECTIVE AMPLIFIER ADJUSTMENT
· · •· · •·
VII
SECTION V
TABLE OF REPLACEABLE PARTS
5-1
GENERAL.
..... . . . . ... . . . . . .. . . .
VII
THE ATTACHED 300A-2 SERVICE MANUAL HAS A SEPA-
RATE INDEX APPEARING ON PAGE 1.
..

III
INSTRUCTION & OPERATING MANUAL
SECTION I
GENERAL
1-1 GENERAL DESCRIPTION
The Model 300A Harmonic Wave Analyzer is a selective voltmeter designed to
measure the individual components of complex waves. The selectivity can be
varied by means of selective amplifiers to measure either closely or widely
spaced harmonics. The instrument cover s the audio spectrum from 30 to
16,000 cps. It has a wide voltage range so that full scale readings may be ob-
tained from 1 millivolt to 500 volts 0
The Model 300A is well adapted to the measurement of the harmonic distortion
in audio frequency equipment of all kinds, broadcast receivers, transmitters;
to determine the harmonic components in ac machinery and power systems; to
the study of induced voltages on telephone lines; and to measurement of hum
components in rectifier circuits.
Other uses include the study of noise by integrating portions of the spectrum
with the selectivity control adjusted for a wide pass band and the checking of
wave filter characteristics with maximum selectivity.
The Model 300A is also useful as a device to measure the amount of cross or
intermodulation products generated by the simultaneous transmis sion of two
frequencies by an audio system or to measure demodulation of a modulated
wave applied through an audio system.
1 -2 SPECIFICATIONS
Complete specifications for the cEiJ Model 300A Harmonic Wave Analyzer will
be found on page 3 of the cEiJ No. 300A-2 Service Manual.
SECTION II
OPERATING INSTRUCTIONS
2-1 230 VOLT OPERATION
This instrument is shipped from the factory with the power transformer pri-
maries connected in parallel for operation from 115 volts. If operation from a
power line of 230 volts is desired, the power transformer primaries must be
connected in series as shown by the "Transformer Detail" on the schematic
diagram in Fig. 3 on page 39 of the No. 300A-2 Service Manual.
Some older instruments have a power transformer with a single primary wind-
ing for operation from 115 volts only.
The 1. 25 ampere slo-blo fuse required for 115 volt operation must be replaced
by a 0.6 ampere slo-blo fuse after changing primary connections from parallel
to series for operation from 230 vo.lts.

IV
2-2 CONTROLS AND TERMINALS
All controls and terminals are fully des cribed on pages 4 and 5 of the r5j:;
No. 300A-2 Service ManuaL
CAUTION
THIS INSTRUMENT IS ACCURATE AT AMBIENT TEMPERATURES OF
APPROXIMATELY 55 TO 95 DEGREES FAHRENHEIT. OTHER AMBI-
ENT TEMPERATURES MAY NECESSITATE REALIGNMENT OF THE
SELECTIVE AMPLIFIER SYSTEM.
2-3 OPERATION
The operation of the Model 300A is divided into two parts. the calibration
adjustment procedure and the measurement procedure.
2-4 CALIBRATION ADJUSTMENT PROCEDURE
This procedure will be found under the heading of CALIBRATION PROCE-
DURE starting on page 11 of the r5j:; No. 300A-2 Service Manual.
See the important operating precautions given in step 26 of CALIBRA TION
PROCEDURE in the No. 300A-2 manual.
2-5 MEASUREMENT PROCEDURE
The instrument must be calibrated before attempting a measurement. In the
following procedure, the voltage being analyzed has a fundamental frequency
of 80 cps and an amplitude of 20 volts. The frequency and amplitude of this
hypothetical voltage have been as sumed to simplify the instructions. Any
voltage between 1 millivolt and 500 volts at any frequency between 30 to
16, 000 cps could be similarly measured. A harmonic frequency must not be
higher 'than 16. 000 cps if the particular harmonic voltage is to be measured.
a. Calibrate the 300A as previously described.
b. Set the METER MULTIPLIER control to 50 (XIOO) and the SET TO 100
FOR VOLT AGE MEASUREMENT control to 100.
c. Set the HALF BAND WIDTH control to 30. See step 26B on page 12 of
No. 300A-2 Service Manual regarding the degree of selectivity neces-
sary for measuring voltages of various frequencies.
d. Set the frequency dial to 80 cps and peak the meter indication by adjust-
ing the FINE TUNING control. The METER SENSITIVITY control should
be adjusted to give a readable indication on the millivoltmeter. The in-
strument is now tuned to measure the amplitude of the fundamental fre-
quency (80 cps) with the harmonics excluded.
e. The actual value of the funda'mental voltage is found by multiplying the
millivoltmeter indication by the multiplying factor shown by the position
of the METER MULTIPLIER control.
J

Example:
METER SE. SITIVITY at 500 (5. a on meter scale) full scale millivolts.
Meter pointer at 2. a therefor e meter actually indicates 200 millivolts.
200 millivolts x 100 (meter multiplier factor) is equal to 20, 000 millivolts
or 20 volts.
2-5 MEASUREMENT PROCEDURE (Contld.)
v
..
£. Turn the frequency dial to 160 cps (second harmonic of 80 cps) and set the
METER SEl SITIVITY and METER MULTIPLIER controls to obtain a read-
able meter indication. Use the FINE TUNING control to peak the meter
indication. The meter indication times the meter multiplying factor will
give the amplitude of the second harmonic.
g. Repeat step f. at as many higher harmonics as desired until the harmonic
voltages become too small to measure. In some cases, the harmonic fre-
quency will be higher than 16, 000 cps which will be outside the range of the
300A.
2-6 MEASUREMENT PRECAUTIONS
The results obtained with the 300A will depend upon how clos~ly the operator
follows afew" simple but very important operating precautions. These pre-
cautions are given in step 26 of PROCEDURE FOR CALIBRATION on page 12
of 1$ o. 300.1\-2 Service Manual.
In addition, a 20 KC filter should be used between the voltage to be measured
and the input terminals of the Model 300A when voltages at frequencies of 5 KC
or 10 KC are being measured. This filter will prevent the fourth harmonic of
the 5 KC volt3.ge or the second harmonic of the 10 KC voltage from entering
the 20 KC seJ.ective amplifier and causing erroneous measur~ments.
2-7 SELEC TIVITY
When operati.ng the Model 300A, it should be borne in mind that the instrument
is a frequency selective, wide range voltmeter whose selectivity is variable.
It is necessary during operation to determine the degree of selectivity desired
and to adjust the instrument correctly to obtain that degree of selectivity.
Determination of the proper selectivity to use in a particular measurement
should primarily be based on the fact that unwanted voltages must be attenu-
ated by the selectivity of the instrument to less than one third of the voltage
under measurement. This attenuation is, in turn, dependent upon the order
of separation of unwanted voltages from the desired voltage, and the relative
magnitudes of the various voltages involved.
Instrument selectivity is controlled by the HALF BAND WIDTH control which
is calibrated from "30" to "145". These calibrations indicate the frequency
separation fr~m the center frequency at which the selectivity characteristics
of the instrument attenuates by 40 db (99%).
Another way of saying the same thing is that the HALF BAND WIDTH calibra-
tions indicate the minimum frequency separation from a 100% voltage which
will permit accurate measurement of a 3% voltage.
It will often be found convenient to use only two degrees of selectivity as ob-
tained by setting the HALF BAND WIDTH control at "145" for minimum

VI
2-7 SELECTIVITY (Contld.)
selectivity or at "30" for maximum selectivity. Us e mlmmum selectivity
for voltages with a fundamental frequency higher than 100 to 300 cps. Use
maximum selectivity for voltages with a fundamental frequency lower than
100 to 300 cps. This system eliminates the necessity of determining whether
an intermediate degree of selectivity offers sufficient attenuation for the case
at hand.
Occasionally, however, it is desirable to use degrees of selectivity which are
intermediate between minimum and maximum. An example follows to illus-
trate a typical case of selectivity determination.
Refer to Fig. 2 on page 38 of the No. 300A-2 Service Manual which shows
the selectivity characteristics of the 300A for the two extremes of the HALF
BAND WIDTH control. A convenient graph for converting attenuation in terms
of decibels to percentage is given in Fig. 9 on page 45 of the No. 300A-2
Service ManuaL
The graphs of Figs. 2 and 9 are used to determine the setting of the HALF
BAND WIDTH control as illustrated in the following:
As sume that it is desired to measure the harmonics of an 80 cps funda-
mental and that harmonics which are 0.50/0 or higher are,of interest.
Unwanted voltages must be attenuated to less than 1/3 of the voltage under
measurement and for this particular case it would be 1/3 of 1/20/0 or 1/6
of 10/0. In other words, when measuring the second harmonic, the funda-
mental must be reduced to 1/6 of 10/0 of its value by the 300A selectivity
characteristics. Referring to Fig. 9, we see that 1/6 of 1% is equivalent
to approximately 56 decibels. Therefore, the HALF BAND WIDTH con-
trol must be adjusted so that the instrument will attenuate by 56 decibels
for a frequency separation of 80 cps.
Refer to Fig. 2 and sketch in a curve similar to the two curves shown.
The new curve should pass through the 56 db point at 80 cps off resonance.
Note the point where the new curve passes the 40 db line. This point has
an abscissa of about 50 cycles off resonance. Therefore, the HALF
BAND WIDTH control should be set at "50" to obtain 56 db attenuation at
80 cps off resonance.
The instrument must then be calibrated using a HALF BAND WIDTH
setting of "50" instead of "30" in steps 20 through 23 of PROCEDURE
FOR CALIBRATION on page 12 of No. 300A-2 Service Manual. See
step 26B on the same page for additional information.
SECTION III
CIRCUIT DESCRIPTION
3- 1 GENERAL
The circuitry of the rFeJ Model 300A Harmonic Wave Analyzer is discussed on
pages 8, 9, 10, and 11 of the (/!j) No. 300A-2 Service Manual.
•

VII
SECTION IV
MAINTENANCE
4-1 CABINET REMOVAL
To remove the instrument from the cabinet it is necessary to unscrew the
eight large Phillips head screws on ~he control panel and slide the instrument
forward out of the cabinet.
In some older instruments, it may be necessary to remove the wire connect-
ing the bottom chassis to the metal plate in the bottom of the cabinet. This
wire will be found on the rear of the instrument.
4-2 TUBE REPLACEMENT
Refer to page 7 of Service Manual No. 300A-2 for complete instructions on
tube replacements.
4-3 LOCAL OSCILLATOR AMPLITUDE ADJUSTMENT
This adjustment can be made at any time as directed in step 2 of PRELIMI-
NAR Y TESTS & ADJUSTMENTS on page 13 of No. 300A-2 Service Manual.
4-4 VOLTAGE REGULATOR ADJUSTMENT
The output of the regulated power supply section in the 300A should be checked
from time to time as directed in step 1 of PRELIMINARY TESTS & ADJUST-
MENTS on page 13 of No. 300A-2 Service Manual.
4-5 HUM BALANCE ADJUSTMENT
The hum balance control R159 is located on the bottom deck of the instrument
next to the heater transformer. The procedure for adjusting this control is
given in FINAL TEST step 8 on page 17 of No. 300A-2 Service Manual.
•
4-6
4-7
BALANCED MODULATOR ADJUSTMENT
The procedure for adjusting the balanced modulator to minimize harmonic
distortion is given on page 18 of No. 300A-2 Service Manual in step 10 under
FINAL TEST.
SELECTIVE AMPLIFIER ADJUSTMENT
The detailed procedure for adjusting the selective amplifier system in the
300A is given on pages 14 and 15 of the No. 300A-2 Service Manual.
SECTION V
TABLE OF REPLACEABLE PARTS
5-1 GENERAL
A table of replaceable parts which is suitable for use with all 300A instruments
is given in the ~ No. 300A-2 Service Manual. This table begins on page 51 of
the manual.

I
•
OPERATION AND SERVICE MANUAL
FOR
MODEL 300A
HARMONIC WAVE ANALYZER
300A-2A
This is a combined Operation and Service Manual for
all c5j; Model 300A Harmonic Wave Analyzers. This
manual contains complete operation and servicing in-
structions for the 300A and may be used in place of
the Instruction and Operating Manual originally sup-
plied with each instrument •
Copyright 1955 by Hewlett-Packard Company
The information contained in this booklet
is intended for the operation and main-
tenance of Hewlett-Packard equipment and
is not to be used otherwise or reproduced
without the written consent of the Hewlett-
Packard Company.
HEWLETT-PACKARD COMPANY
275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA, U.S. A.
300A002

, ..
Typical Front View of -hp- Model 300A Harmonic Wave Analyzer
'.