HP 339A - Oscillator Total Harmonic Distortion Test

Model
339
A
Section
IV
Table
4-4.
Oscillator
Frequency
Accuracy
Test.
Frequency
339A
Frequency
Range
Setting
Frequency
Counter
Indication
(Period)
10
Hz
102.04
mSec.
-
98.04
mSec.
20
Hz
X
10
51 .020
mSec.
-
49.01
9
mSec.
50
Hz
20.408
mSec.
-
1
9.608
mSec.
100
Hz
10.204
mSec.
-
9.803
mSec.
100
Hz
10.204
mSec.
-
9.803 mSec.
200
Hz
X 100
5.1020
mSec.
-
4.9019 mSec.
500
Hz
2.0408
mSec.
-
1 .9608
mSec.
1 kHz
1
0204
mSec.
-
.9803
mSec.
J^kHz
1020.4
MSec.
-
980.3
MSec.
kHz
927.64
M
Sec.
-
891.26 MSec.
1 ,2
kHz
850.34
MSec.
-
816.99 MSec.
1
.3
kHz
784.93
MSec.
-
754.14
M
Sec.
1 .4 kHz
728.86 MSec.
-
700.28 MSec.
1.5
kHz
680.27 MSec.
-
653.59
m
S
ec
.
1.6
kHz
637.75 MSec.
-
612.74
M
Sec.
1 .7
kHz
600.24
jxSec.
-
576.70
/-tSec.
1.8
kHz
X IK
566.89 MSec.
-
544.66 MSec.
1 .9
kHz
537.05
MSec.
-
51
5.99
m
S
ec.
2.0
kHz
510.20
M
Sec.
-
490.19 MSec.
3.0
kHz
340.13
M
Sec.
-
326.79 MSec.
4.0 kHz
255.10
M
Sec.
-
245.09 MSec.
5.0
kHz
204.08 MSec.
-
196.08
MSec.
6.0
kHz
170.06 MSec.
-
163.39 MSec.
7.0
kHz
145.77 MSec.
-
140.05
MSec.
8.0
kHz
127.55 MSec.
-
122.54
M
Sec.
9.0
kHz
1
13.37
MSec.
-
108.93
M
Sec.
10.0
kHz
102.04 MSec.
-
98.039 MSec.
10
kHz
102.04 MSec.
-
98.039
M
Sec.
20
kHz
51.020
/xSec.
-
49.019
^Sec.
50
kHz
X
10 K
20.408 MSec.
-
19.608 MSec.
kHz
10.204 MSec.
-
9.8039 MSec.
^£9 kHz
9.361
5
MSec.
8.9944
MSec.
b.
Connect the
equipment as
shown in
Figure
4-7.
c.
Adjust the
Frequency
Counter
controls to measure
period.
d. The
339A
10 Hz
frequency
should
be within
the
limits
listed in
Table
4-4.
e.
Verify the 339A
Oscillator
Frequency
Accuracy for
each
frequency
listed
in Table
4-4.
4-19. Oscillator
Total
Harmonic
Distortion
Test.
Equipment
Required:
^Spectrum
Analyzer (-hp-
Model 3044A)
^Tuneable
Notch
Filter (-hp-
Model 339A)
600 ohm
Resistive Load
(-hp- 1 1095A)
a.
Set
the
339A
controls as
follows:
FUNCTION
OSCillator
LEVEL
FREQUENCY
10
Hz (1.0
x
10)
FREQUENCY
VERNIER
CAL
OSCILLATOR
LEVEL
3
V
b.
Connect
the
equipment
as
shown
in
Figure
4-8.
c.
Adjust
the
339A
OSCILLATOR
LEVEL
vernier
for an
output
level
of 3
V
rms as
indicated
on the
339A
meter.
d.
Set
the
Tuneable
Notch
Filter
(339A)
Frequency to
10
Hz
and set
the
Function to
Input
Level.
Adjust
the
Input
Range
control
as
necessary
to
obtain
an
on-scale
meter
indication
as
near
full-scale
as
possible.
e.
Set the
Spectrum
Analyzer
(3571 A)
controls
for an
input
impedance
of 1
M f2
,
an
input
range
of
+
10dB
V,
a
bandwidth
of 3
Hz.
and a
relative
display
reference.
f.
Tune
the
Spectrum
Analyzer
to the
exact
frequency
of the 339A
under
test by
varying
the
Synthesizer
(3330B)
frequency
until
the
Spectrum
Analyzer
indicates
maximum
level.
Enter
this
frequency
as
both the
output
frequency
and
step
frequency
of the
Synthesizer.
g.
Reference
the
Spectrum
Analyzer
to the
amplitude
of
the 339
A
fundamental
frequency
by
pressing
the
Enter
Offset
button.
(Observe
a
Spectrum
Analyzer
display of
00.00
dB.)
h.
Adjust
the
Tuneable
Notch
Filter
controls as
necessary
to
make
a
distortion
measurement.
(The
purpose of
this
step
is
to null the
fundamental
frequency
of
the
339A
Oscillator
output.
This
puts
the
distortion
products
within
the
dynamic
range of
the
Spectrum
Analyzer.)
i.
Step
the
Synthesizer
frequency
to
the second
harmonic
frequency
of
the 339A
output.
j.
The
amplitude
of
the second
harmonic
frequency,
relative
to
the
fundamental
frequency
is
determined by
adding
the
Spectrum
Analyzer
display
reading and
the
range
setting
of
the
Notch
Filter. (As
an
example: If the
Notch
Filter
distortion
range
control
is set to
-80
dB and
the
Spectrum
Analyzer
display
indicates
-23
dB the
amplitude
of
the
second
harmonic
is
-103
dB,
relative to
the
fundamental.)
Record
the
amplitude
reading
of
the
second
harmonic.
k.
Step
the
Synthesizer
frequency
to
the
frequency
of
the
third
harmonic.
l.
Determine
the
relative
amplitude
of
the third
harmonic
by
adding
the
Spectrum
Analyzer
display
reading
and
the
range
setting of
the
Notch
Filter.
Record
the
amplitude
reading
of the
third
harmonic.
4-7