Spectrum Measurements
R&S
®
ESR
331
User Manual 1175.7068.02 ─ 12
Figure 6-9: Intermodulation products PU1 and PU2
The intermodulation product at f
I2
is generated by mixing the 2nd harmonic of useful
signal P
U2
and signal P
U1
, the intermodulation product at f
I1
by mixing the 2nd harmonic
of useful signal P
U1
and signal P
U2
.
f
i1
= 2 × f
u1
– f
u2
(6)
f
i2
= 2 × f
u2
– f
u1
(7)
Dependency on level of useful signals
The level of the intermodulation products depends on the level of the useful signals. If
the two useful signals are increased by 1 dB, the level of the intermodulation products
increases by 3 dB, which means that spacing a
D3
between intermodulation signals and
useful signals are reduced by 2 dB. This is illustrated in
Measurements
