More Complex Programming Examples
R&S FSMR
1166.3363.12 7.22
E-1
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 FSMR is used for measurements (SetupInstrument).
REM ************************************************************************
Public Sub TOI()
result$ = Space$(100)
'--------- R&S FSMR default setting ----------------------------------------
----
CALL SetupStatusReg
'Set status registers
CALL IBWRT(analyzer%,"*RST")
'Reset instrument
CALL IBWRT(analyzer%,"INIT:CONT OFF")
'Single sweep
CALL IBWRT(analyzer%,"SYST:DISP:UPD ON")
'ON: display on
'OFF:
off
'--------- Set frequency ---------------------------------------------------
CALL IBWRT(analyzer%,"FREQ:STARt 85MHz;STOP 125 MHz") 'Span
'--------- Set level -------------------------------------------------------
CALL IBWRT(analyzer%,"DISP:WIND:TRAC:Y:RLEV –20dBm") 'Reference level
CALL IBWRT(analyzer%,"INIT;*WAI")
'Perform sweep with sync
'--------- TOI measurement -------------------------------------------------
CALL IBWRT(analyzer%,"CALC:MARK:PEXC 6DB")
'Peak excursion
CALL IBWRT(analyzer%,"CALC:MARK:FUNC:TOI ON") 'Switch on TOI measurement
CALL IBWRT(analyzer%,"CALC:MARK:FUNC:TOI:RES?") 'and read out results
CALL IBRD(analyzer%,result$)
'--------- Read out result ------------------------------------------------
Print "TOI [dBm]: ";result$
END SUB
REM ************************************************************************
Summary of Contents for FSMR
Page 1: ...R S FSMR Measuring Receiver Operating Manual Test Measurement Operating Manual 1313 9723 12 01...
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Page 26: ...Contents Preparing for Operation R S FSMR 1155 5047 12 I 1 2 E 2 Fig 1 1 Front View...
Page 28: ...Front View R S FSMR 1166 3363 12 1 2 E 2 Fig 1 1 Front View...
Page 30: ...Front View R S FSMR 1166 3363 12 1 4 E 2 Fig 1 1 Front View...
Page 32: ...Front View R S FSMR 1166 3363 12 1 6 E 2 Fig 1 1 Front View...
Page 34: ...Front View R S FSMR 1166 3363 12 1 8 E 2 Fig 1 1 Front View...
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Page 130: ...Menu Overview R S FSMR 1166 3363 12 3 42 E 3 Menu Overview another Keys MKR Key...
Page 141: ...R S FSMR Menu Overview 1166 3363 12 3 53 E 3 LOCAL Menu LOCAL...
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