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Model
654A
Table
5-2.
Frequency
Accuracy
Check
odel654A
COUNTER
FREQUENCY
)
DIAL
RANGE ACCURACY
INDICATION
:!: 3%
:!:
3'*
:!:3
' 7 0
:!:3
%
:!:
3%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!: 2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
2%
:!:
4
%
:!:4%
Counter
set to
Period Average
lOOms :!:3ms
40ms :!: 1.2ms
20.0ms
:!: 0.6111s
12.51115
:!:.375111S
10.Oms
:!:
0.3111s
5-12
.
10_
Oms :!: O.
2ms
4.00ms :!:
.08ms
2.00111s
:!: 0.04ms
1.25ms
:!:.025ms
I
.00ms
:!: 0.02ms
Counter set to
Frequency
1,000Hz :!: 20Hz
2500Hz:!:
50Hz
5,0001-lz :!: 100l-lz
8,000Hz :!: 160Hz
10,000Hz :!:
200l-lz
10.OkHz :to.2kHz
25kHz:!: .5kHz
50.0kHz :!: 1.0kHz
80kHz:!: 1.6kHz
100kHz:!: 2kHz
100kHz:!: 2kHz
250kHz:!:
5kHz
500kHz:!:
10kHz
800kHz:!:
16kHz
I ,000kHz :!:
20kHz
I ,000kl-lz :!:
20kHz
2,500kHz
:!:
50kHz
5,000kHz
:!: 100kHz
8,000kHz
:!: 320kHz
10,000kHz :!:400kHz
Section V
in
step
b. Set IMPEDANCE to
75
UNBAL;
in
step c.
The ac differential voltmeter indication
should
be between
.8573V rms and
.8747V
rms.
b.
If
the tolerances are not met, first assure that the
50
ohm
output is correct (Paragraph 5-10) then
troubleshoot the instrument. The trouble will
most probably be in either the
50 ohm
or 75 ohm
impedance networks on the A4 board.
135 BAL AMPLITUDE ACCURACY.
a.
Connect the equipment (shown in Figure
5-2),
in
the following manner:
1)
Connect
a 67.5
ohm
resistor (use two 135 ohm
resistors
in parallel
,
R I
and
R2)
across
two BNC
to Binding Post Adapters
as shown
in Figure 5-2.
2)
Connect
the
adapters to
the
two output
terminals of the 654A.
3)
Connect the ae voltmet er across the resistor
which is connected to the
654A
UNBAL
terminal.
b. Set the 654A controls
as
in Paragraph
5-IOb
except set
IMPEDANCE to 135 BAL.
c.
Record the ac differential voltmeter indication
.
d. Disconnect the voltmeter from the one resistor
and record the voltage
across
the other resistor
(connect the ground lead
as
before).
e.
Add the two voltages recorded in
steps
c and d.
The total vol tage
should fall
between I .150V rms
and
1.174V rms, verifying
an
absolute level of
+lOdBm, +/-1
%.
f. If the tolerances
are
not met troubleshoot the
instrument; the most likely problem would be the
135
ohm
impedance network
on
the A4 board.
I
2.5
5
8
10
I
2.5
5
8
10
I
2.5
5
8
IO
I
2.5
5
8
10
I
2.5
5
8
10
I
2.5
5
8
10
XIO
XIO
XIO
XIO
XIO
XIOO
XIOO
XIOO
XIOO
XIOO
XIK
XIK
XIK
XIK
XIK
XIOK
XIOK
XIOK
XIOK
X10K
XIOOK
XIOOK
XIOOK
XIOOK
XIOOK
XIM
XIM
XIM
XIM
Xllvl
TEST OSCILLATOR
hp654A
r@\
0
[D
@l
4)
8
@
o:::r:rn
Of
~
"""''.
'6'-
...;;;;;----
- - - - ' ( -
~~-
'
500 FEED-THRU
TERMtNATION
hp
II 048C
,--------~--~I
: 750 FEED-THRU
:
: TERMINATION
I
:
L
np
II094C
I
I
MULTI- FUNCTION METER
hp 3450B
III
I
~
~I
~
WITH
OPT.
001
~
CABLE
hp IIOOIA
'-- - - -w:e::J>- - - - - - - -
_' _ (J:1)-_____________----./
Figure 5-1. Amplitude Accuracy Checks - UNBAL
or
5-3
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