Chapter 4 205
Key Function Descriptions
Key Descriptions
This is also referred to as the frequency analog voltage
(FAV). Connector J8 is labeled LO SWP|FAV OUTPUT,
(or LO SWP 0.5 V/GHz on older spectrum analyzers).
When using an 8560 E-Series or EC-Series with a
tracking generator such as an Agilent 85640A, this
softkey must be activated. Pressing
PRESET does not
change the selection of FAV as the output for J8.
If the preselected external mixer mode is selected,
rear-panel output J8 is automatically switched to the
0.5 V/GHz (FAV) mode. The actual output at J8
becomes 1.5 V/GHz, referenced to the LO frequency.
The 1.5 V/GHz of the LO frequency is required for the
Agilent 11974 Series preselected external mixers.
Front-panel key access:
AUX CTRL
2BWMETHOD Makes adjacent channel power (ACP) measurements
using two different resolution bandwidths and
measuring transient and random peak power. This
method is meant for use with burst signals. The sweep
time is set to 600 times the burst period. Two sweeps
are made, one in each of the two resolution bandwidths,
and positive peak detection is used. This method
supports 1993 RCR standards for PDC systems.
The algorithm used for this method assumes that the
power in the adjacent channels consists of two types of
power: impulsive power (transients due to enabling and
disabling the carrier power) and random power
(noise-like signals due to the intermodulation of
noise-like modulation in the main channel). The
characteristics of these two types of power change
differently with resolution bandwidth changes, so they
can be computed algebraically from measurements in
two bandwidths.
The impulsive powers for all frequencies within each
adjacent channel are converted to an equivalent
voltage. These voltages are assumed to be in phase so
they are added to compute a peak voltage in the
channel and a peak power is computed. The random
powers are all added within a channel to give a peak
random power. The peak random power is added to the
peak impulsive power to give a peak weighted power.
Front-panel key access:
MEAS/USER
3dBPOINTS When using 3dB POINTS, a peak search is performed
and the 3 dB bandwidth of the largest on-screen signal
is displayed in the message area.
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