Model 8642A/B
Operation
MODULATION, AM
Description The Signal Generator can amplitude modulate its RF output either with a variable
internal modulation oscillator and/or with an ac- or dc-coupled external source
applied to the AM/PULSE INPUT.
When amplitude settings exceed +14.0 dBm (1.12V, 121.0 dBuV, 2.25 EMF V, and
127.0 dB EMF uV), the AM depth setting is limited. (Refer to Table 3-18 on page
3-102.)
Table 3-17. AM Operating Characteristics
Electrical
Characteristics
AM Depth
Resolution
AM Indicator Accuracy
(1 kHz rate, up to 90% AM)
AM Distortion at 1 kHz rate
AM 3 dB Bandwidth
(Depth <90%)
Incidental *M
(1 kHz rate and 30% AM)
1
lt is possible to set AM with an outpu
2
Specific band information is available
3
AM bandwidths up to 100 kHz can be
Performance Limits
0% to 99.9%
0.1%
±(3.5%
of setting +1% AM)
±(5%
of setting ±1% AM)
8642A Bands 1-8;
8642B Bands 1-9
<1%
<2%
<4%
8642A Band 9, HET;
8642B Band 10, HET
<2%
<4%
<6%
dc to 100 kHz
20 Hz to 100 kHz
dc to 20 kHz
20 Hz to 20 kHz
<0.2 radians peak
t amplitude above this limit. However, it
n Table 3-11.
obtained by selecting Special Function
Conditions
Output Amplitude <+10 dBm
1
(707 mV, 1.41 EMF V, 117.0 dB
M
V,
123dBEMF
M
V)
8642A bands
3
1-8, HET;
8642B bands 1-9, HET
8642A band
3
9,
8642B band 10
0% to 30% AM
30%
to 70% AM
70%
to 90% AM
0% to 30% AM
30%
to 70% AM
70%
to 90% AM
External dc, bands
2
1, 5 thru 10
External ac and internal,
bands
3
1, 5 thru 10
External dc, bands
23
2, 3, 4
External ac and internal, bands
23
2, 3,
s modulation characteristics are not specified.
8 (Prefer Heterodyne Band).
4
Procedures Note: Put the instrument in its initialized state by selecting ( INSTR PRESET J.
AM can be configured to use either the Signal Generator's internal modulation
oscillator, an external source, or combinations of the two sources.
3-97
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