Keysight M1970 Series, Руководство пользователя

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Operation 2
Keysight M1970 Series User’s Guide 39
Signal ID
Image Suppress
The Image Suppress mode of Signal ID mathematically removes all image and
multiple responses of signals present at the mixer input. Two hidden sweeps are
taken in succession. The second sweep is offset in LO frequency by 2*IF/N. For
each point in each trace, the smaller amplitude from the two traces is taken and
placed in that point in Trace 1. Responses of each trace that lie on top of one
another will remain and are valid signals, others are images and are suppressed.
In the Image Suppress mode, synchronization is ensured by first turning off Signal
ID, initiating a single sweep, then turning on Signal ID followed by two single
sweeps.
Image Shift
Like the Image Suppress mode, Image Shift is a two sweep sequence. The data
from the first sweep is placed in Trace 1 and the data from the second (LO
frequency shifted by 2*IF/N) sweep is placed in Trace 2. Signal responses of
Trace 1 and Trace 2 that have the same horizontal position are considered to be in
the current band and therefore can be analyzed with the amplitude and frequency
measurement systems of the SA. All other responses are invalid and should be
ignored.
To synchronize in the Image Shift mode, turn off Signal ID and then initiate a
single sweep. Then turn on Signal ID and initiate two single sweeps. The results of
the first sweep after Signal ID is turned on are available in Trace 1. The next sweep
is shifted and the data from that sweep is available in Trace 2. The unshifted and
shifted data can then be compared.
NOTE
This function takes control of and uses Trace 1. Any data in this trace prior to
activating Image Suppress will be lost.
NOTE
This function takes control of and uses Trace 1 and Trace 2. Any data in these
traces prior to activating Image Shift will be lost.