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Model 654A
:Jde1654A
C
INPUT
IMPEDANCE
50 UNBAL
75 UNBAL
135 BAL
150 BAL
should fall
~rifying
an
600 BAL
shoot the
uld be the
-hp- Part No.
11050A
HOI-11050A
HII-11050A
H12-11050A
H10-11050A
SectIOn V
Tabl e 53Therm aI Converters or Leve
I FI
atness Checks.
(See Paragraph 5-16 for explanation)
Board.
c.
Sct the reference supply for minimum output
voltage and record, in Table 5-3, the thermal
converter output voltage indicated on the dc null
volt meter.
d. Using the formula given below, calculate the
voltage deviation which represents a change of
+/-D.5%; record this in the last
column
of Table
5-3.
...
.
1
2E (% change)
+/- t.E
=
100
.. XIK
. +10,0
t.E
=
maximum allowable deviation from E
o
UNBAL
E
=
thermal converter output voltage
for OdBm
% change
=
(+/-) 0.5
%
4A meter.
Example:
If E
=
7mV
-e
5-3
:
use
2 x 7 x 10- 3 x (+/-)0.5
Then +/- t.E
=
2
+/- 70uV.
;-3) which
[0
A UNBAL
) build the
4).
- - - - - - NOTE - - - - - -
The factor 2 is included in the formula as
the thermal
device.
converter is a square law
e. Adjust the reference supply for null indication on
the dc null meter.
f. Sweep the 654A slowly over the frequency range
of 10Hz to 10MHz; the dc null meter indication
should not vary more than +/-t.E (calculated in
step
d of this Paragraph) from null. This verifies
a
level flatness, referenced to 1kHz, of +/-0.5
%
at an
output
level of + I OdBm.
g.
Reset the 654A frequency to I kHz and the
10dBm step attenuator to 0 position and repeat
Input Level
+10dBm
OdBm
+IOdBm
OdBm
+IOdBm
OdBm
+IOdBm
OdBm
+IOdBm
OdBm
Output Voltage
(dc)
+/-0.5
%
deviation
mV
mV
+/-
+/-
uV
uV
mV
mV
+/-
+/-
uV
uV
mV
mV
+/-
+/-
uV
uV
mV
mV
+/-
+/-
uV
uV
mV
mV
+/-
+/-
uV
uV
steps
c through f of this paragraph to verify a
flatness of +/-0.5
%
at
an
output level
of
OdBm.
h.
If the tolerances are not met, first check the 75
UNBAL
flatness
(Paragraph
5-17)
before
performing the calibration of Paragraph
5-67.
5-17. 75 UNBAL FLATNESS
CHECK.
a. Perform the procedure of Paragraph 5-16
steps
a
through
g
with the following changes:
in step a. Set IMPEDANCE to 75 UNBAL;
in
step
b. Use the 75 ohm thermal converter
(Table 5-3).
b. If the tolerances are not met, perform the
calibration of Paragraph 5-66.
REFERENCE SUPPLY
r-----------------,
I
RI
I
6500
I
I
r.:
I
R2
I
L
500
J
I
I
I
~~~v
>--~~6
>---4----~
L ____________________ J
65."-tl
-
18'l1
Parts list:
RI: R fxd met flm 6500 ohms +/-1
%
-hp- 0811-0392
R2: R var 500 ohms
+/-5%
-hp- 2100-D324
R3: R var 50 ohms
+/-5%
-hp- 2100-1481
BTl: 1.34 V Mallory RM42R
Figure 54. Reference Supply
5-5
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