Rohde & Schwarz R&S FSL3 - Page 1635

R&S FSL Using Marker and Delta Marker
1300.2519.12 7.7 E-11
'––––––––– Set frequency –––––––––––––––––––––––––––––––––––––––––––––––––––
CALL InstrWrite(analyzer,"FREQ:SPAN 1MHz")
'Span
CALL InstrWrite(analyzer,"BAND:RES 30kHz")
'
Resolution bandwidth
CALL InstrWrite(analyzer,"INIT;*WAI") 'Perform sweep with sync
'––––––––– Measure 60 dB value –––––––––––––––––––––––––––––––––––––––––––––
CALL InstrWrite(analyzer,"CALC:MARK:PEXC 6DB")
'Peak excursion
CALL InstrWrite(analyzer,"CALC:MARK:STAT ON")
'Marker1 on
CALL InstrWrite(analyzer,"CALC:MARK:TRAC 1")
'Assign marker1 to trace1
CALL InstrWrite(analyzer,"CALC:MARK:MAX") 'Set marker1 to 100 MHz
CALL InstrWrite(analyzer,"CALC:MARK:FUNC:NDBD 45dB")
'Read out bandwidth measured at
'45 dB
CALL InstrWrite(analyzer,"CALC:MARK:FUNC:NDBD:RES?")
CALL InstrRead(analyzer,result$)
result60 = Val(result$)
'––––––––– Measure 3 dB down value–––––––––––––––––––––––––––––––––––––––––
CALL InstrWrite(analyzer,"CALC:MARK:FUNC:NDBD 3dB")
'Read out bandwidth measured at
'3 dB
CALL InstrWrite(analyzer,"CALC:MARK:FUNC:NDBD:RES?")
CALL InstrRead(analyzer,result$)
result3 = Val(result$)
'––––––––– Read out shape factor––––––––––––––––––––––––––––––––––––––––––––
Print "Shapefaktor 60dB/3dB: ";result60/result3
END SUB
REM
************************************************************************
Measuring the Third Order Intercept Point
The third order intercept point (TOI) is the (virtual) level of two adjacent useful signals at which the
intermodulation products of third order have the same level as the useful signals.
The intermodulation product at f
S2
is obtained by mixing the first harmonic of the useful signal P
N2
with
signal P
N1
, the intermodulation product at f
S1
by mixing the first harmonic of the useful signal P
N1
with
signal P
N2
.
f
s1
= 2 x f
n1
– f
n2
(1)
f
s2
= 2 x f
n2
– f
n1
(2)
The following example is based on two adjacent signals with a level of –30 dBm at 100 MHz and
110 MHz. The intermodulation products lie at 90 MHz and 120 MHz according to the above formula. The
frequency is set so that the examined mixture products are displayed in the diagram. Otherwise, the
default setting of the R&S FSL is used for measurements (SetupInstrument).