Model
8642A/B
General
Information
Table
1-2.
Supplemental
Characteristics
(1 of
2)
Supplemental characteristics are typical, but non-warranted performance parameters, intended to be useful
in
instru-
ment applications.
FREQUENCY
Underrange:
10 to 100 kHz.
Heterodyne
Mode
(HET,
Special
Function
8):
The 8642A/B
can derive its output through a heterodyne mode
in
the
carrier frequency range from
0.1
MHz to 132.1875 MHz.
This improves modulation and some frequency sweep
characteristics at lower carrier frequencies.
Frequency
Switching
Time
to
Within
100
Hz
of
Final
Frequency:
Processor
Delay
I
Frequency
Sellling
Tolal
Time
20
rns I
65
rns
85
rns
SPECTRAL
PURITY
SSB
Phase
Noise
at
1
GHz
Carrier
Frequency
(dBc
in
1
Hz
bandwidth):
10
100
1
10
20
100
200
1
Hz
Hz
kHz
kHz
kHz
kHz
kHz
MHz
-40
-75
-98
-131
-138
-146 -147
-147
Measured
SSB
Phase
Noise
at
1
GHz:
~~"'-'-~....,,~~r-'-'·'·'I·
·-··.···n·'...,...,.,
N
-20
t==±==l==~----:=!==.tl
=~
~
·-40
--I
j
=::,
~~:::''''':::'':::..''
t==::t:=::::t==1=~
i-lao,
~-."
"-120
."",
'"
ffi
-140
-160
C=±==t==l=:=±==:t:
I=j
10
100 1k 10k 100k
1M
Offset
Frequency, Hz
SSB
AM
Noise
Floor
at
200
kHz
Offset,
+16
dBm:
<-157
dBc/Hz, band 2 through
9.
<-150
dBclHz,
band
10.
MODULATION
External
Input
Impedance:
600 ohms, ± 1 0%.
10M
10
MHz
-154
External
Input
Level
Required:
1 Vpeak for specified accu-
racy. Front-panel annunciators indicate application
of
1V peak signal ±5%, 20 Hz
to
100 kHz. When greater
accuracy
is
required, modulation drive voltage should
be monitored externally.
Modulation
Source
Capability: All modulation types can be
driven with either
an
internal or external modulation
source. AM, FM, and
<PM
can also be driven simultane-
ously by both internal and external modulation sources.
Mixed
Modulation
Types:
Any
two
modulation types can
be simultaneously selected except for
FM
+
<PM
and
AM
+ pulse modulation.
FREQUENCY
MODULATION
Carrier Stability
in
FM
Mode:
AC
FM: Same
as
CWo
DC
FM:
<4
kHz/hour, 8642AfB bands 1-9, HET.
<8
kHz/hour, 8642B band 10.
FM
SIereo
Separation,
Ext
de·
Coupled,
HET
Band
(Special
Function
8):
>50
dB, 1 kHz rate, 75 kHz deviation.
Low
Distortion
FM/1'M
(Special
Function
5
or
112):
Distortion
in
either FM or
<PM
can
be
reduced with this function.
FM
stereo separation unaffected.
FM
Distortion
in
Special
Function
7:
<0.03% THO, <1/15
maximum deviation, external rates
<50
kHz and inter-
nal rates <15.8 kHz.
FM
Pre-emphasis (Special Function 6):
Provides
pre-
emphasis
in
FM with a 750 JiS time constant. This is
useful when testing FM communications receivers.
AMPLITUDE MODULATION
(for
VOR,
ILS,
Avionics Applications)
AM
Phase
Shift,
DC
Coupled,
for Carrier
Frequencies
From
108
MHz
to
118
MHz:
30 Hz rate:
<±0.01°.
30 Hz
to
10 kHz rate:
<±3°.
Difference from 9 kHz to
11
kHz rates:
<2°.
AM
Flatness,
DC
Coupled
External
AM:
<0.04 dB, 90 to 150 Hz, 108 to 118 MHz and 329
to
335
MHz.
«0.00092
DDM
@
20%
AM
and
<0.0019 DDM @ 40% AM.)
<0.1 dB, 9 to
11
kHz, 108
to
118 MHz.
OUTPUT
Absolute
Accuracy:
±3
dB, output level
<-127
dBm.
Outpul
Level
Switching
Time:
<100
ms from receipt
of
last
controller command.
Amplitude
Sweep,
in
CW
and
Angle
Modulation
Modes:
Range:
20
dB
log (or linear with Special Function 122)
sweep (10 dB underrange available).
Sweep
Time:
20 ms minimum, 999s maximum.
Accuracy:
± 1
dB
over
highest 10 dB.
±3
dB
over sec-
ond highest 10 dB.
Attenuator
Range
Hold
(Special
Function
9):
The internal
step
attenuator can be fixed and the electronic level
vernier varied up
to
30 dB for monotonic level setting.
This
is
useful
in
measuring
of
receiver
squelch
hysteresis.
[-I
3
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