HP HP 8753E, User Manual, Page: 400 / 699

n
The frequency of the incoming signal should be within -0.5 to MHz of the selected
frequency or the analyzer will not be able to phase lock to it.
CW Frequency
Range in
External Source Mode.
300 to 3 (6 for Option 006)
Compatible Sweep Types.
The external source mode will only function in CW time sweep.
If the instrument is in any other sweep type when external source is activated, the warning
message
CHANGED TO CW TIME MODE
will appear on the display.
External Source Requirements.
The external source mode has spectral purity and power
input requirements, which are described in Chapter 7, “Specifications and Measurement
Uncertainties.
Input Channel: R
Capture Range. In either automatic or manual mode, you can enter the frequency of the
. . . . . . . . . . . . . . . . . . . . .
actual signal must be within a certain frequency capture range as shown in 6-8.
6-8. External Source Capture Ranges
cw
MHz MHz of CW frequency
of nominal CW frequency
0.6 to + MHz of nominal CW frequency
If the incoming signal is not within the capture range, the analyzer will not phase lock
correctly.
Locking onto a signal with a frequency modulation component. Although the analyzer may
phase-lock onto a signal that has FM, it may not accurately show the signal’s amplitude. The
accuracy of such measurements depends greatly on the IF bandwidth you choose. Use the
widest IF bandwidth available (3 if this problem occurs.
Tuned Receiver Mode
. . . . .
ii
. . . .
. . . . .. . .
If you press the analyzer receiver operates
independently of any signal source.
The following features and limitations apply to the tuned receiver mode:
n
It is a fully synthesized receiver; it does not phase-lock to any source.
n
It functions in all sweep types.
n
It requires a synthesized CW source whose is input to the analyzer’s external
frequency reference.
For more information on using the tuned receiver mode, refer to Chapter 2, “Making
Measurements
Application and Operation Concepts 18