Giga-tronics 8003, Руководство по эксплуатации

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Operation
Manual 20791, Rev. C, June 2001 2-89
2.11.3 Searches on Frequency Selective Devices
One of the most common searches on frequency selective devices is the
-3 dB point
. This is easily
done on the 8003 Analyzer by pressing
[CURSOR]
followed by the [ SEARCH ] softkey.
Note the Cursor position in relation to the target -3 dB point on the trace. Press [ SEARCH LEFT ] to
search to the left of the cursor for the -3 dB point. Press [ SEARCH RIGHT ] to search to the right of the
cursor for the -3 dB point. If the search is successful, the frequency and relative power level are shown in
the active entry area.The active entry area on the screen shows that the default search value is -3 dB.
You can change this to any negative or positive value by entering the desired value on the numeric
keypad and pressing
[GHz/dB]
. For example, Figure 2-46 shows the -30 dB point on a high pass filter
(sometimes used to determine filter cutoff).
Figure 2-45: -3 dB Point (Low Pass Filter) at 3.175 GHz
SEARCH
RIGHT
BAND-
WIDTH
SEARCH
LEFT
SEARCH
VALUE
CURSOR
RETURN
STRT
2.500 GHz
STOP
CH1: SW A -PC CRSR -3.00 dB
2.0
dB/ H REF -0.00 dB
4.000 GHz
MAX
CRSR 3.175 GHz
MIN
SRCH -3.00 dB
3.175 GHz
1
VALUE FOUND: TRACE HOLD