Tektronix SPECMON3 Manual page 277

Pulsed RF
Setting
Modulation type
Pulse Frequency Reference
Auto
Freq Offset
Chirp BW
xxx
Modulation Type
Frequency estimation is performed by the instrument using selectable methods, depending on signal type.
The selections for modulation type are CW (constant phase), CW (changing phase), Linear Chirp and
Other. Select the method of frequency method based upon a best match to your signal based on the
following descriptions:
CW (constant phase): The signal is not designed to change in either frequency or phase during the
measured pulse train.
CW (changing phase): The signal does not change the carrier phase within each pulse, although it
could change the phase from one pulse to another pulse. The signal is not designed to make frequency
changes.
Linear Chirp: The signal changes frequency in a linear manner during each pulse. The signal has the
same carrier phase at the same time offset from the rising edge of the pulse.
Other: The signal is not one of the listed types. You must manually enter the Frequency Offset value.
The following table maps the appropriate signal type selection with the signal characteristics.
Signature
CW
LFM
xxx
SPECMON3 & SPECMON6 Printable Help
Description
Specifies which algorithm to use for estimating frequency error.
Specifies the method used to determine the pulse frequency error and if applicable,
the chirp slope.
Selecting Auto causes the instrument to calculate the frequency offset and if applicable,
the chirp slope.
If Auto is not enabled, specify the value for frequency offset here. If Auto is enabled, the
offset is set to zero and this readout displays the calculated frequency error.
If Auto is not enabled, specify the value for Chirp Slope here. If Auto is enabled,
this readout displays the calculated Chirp slope. This setting is used only when the
modulation type is set to Linear Chirp.
Phase offset from one pulse to another
Zero
CW Constant Phase
Linear Chirp
Freq Estimation Tab
Any (unknown)
CW Changing Phase
N/A
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