Remote Control
R&S
®
ESRP
975
User Manual 1175.7445.02 ─ 08
Print "Shapefaktor 60 dB/3 dB:";result60/result3
END SUB
REM ************************************************************************
11.17.2.2
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 har-
monic of the useful signal P
N1
with signal P
N2
.
f
s1
= 2 × f
n1
– f
n2
(1)
f
s2
= 2 × 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 accord-
ing 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
ESRP is used
for measurements (
SetupInstrument
).
REM ************************************************************************
Public Sub TOI()
result$ = Space$(100)
'--------- R&S FSV default setting ----------------------------------------
CALL SetupStatusReg 'Set status registers
CALL InstrWrite (analyzer, "*RST") 'Reset instrument
CALL InstrWrite (analyzer, "INIT:CONT OFF") 'Single sweep
CALL InstrWrite (analyzer, "SYST:DISP:UPD ON")
'ON: display on'OFF: off
'--------- Set frequency ---------------------------------------------------
CALL InstrWrite (analyzer, "FREQ:STARt 85 MHz;STOP 125 MHz")
'Span
'--------- Set level -------------------------------------------------------
CALL InstrWrite (analyzer, "DISP:WIND:TRAC:Y:RLEV -20 dBm")
'Reference level
CALL InstrWrite (analyzer, "INIT;*WAI") 'Perform sweep with sync
'--------- TOI measurement -------------------------------------------------
CALL InstrWrite (analyzer, "CALC:MARK:PEXC 6 DB")
'Peak excursion
CALL InstrWrite (analyzer, "CALC:MARK:FUNC:TOI ON")
'Switch on TOI measurement
CALL InstrWrite (analyzer, "CALC:MARK:FUNC:TOI:RES?")
'and read out results
CALL InstrRead(analyzer, result$)
'--------- Read out result ------------------------------------------------
Print "TOI [dBm]:";result$
Remote Control – Programming Examples
