R&S FSL Noise Figure Measurements Option (K30)
1300.2519.12 2.107 E-11
the noise source is not converted by a further receive path of the mixer. The noise of the noise source
a
t the receive frequency must not be reduced. The insertion loss must be considered, if applicable.
With this test setup, the measurement on a mixer without sideband suppression corresponds to the
measurement on a single–sideband mixer. As in that case, set the image rejection in the Frequency
Settings dialog box to a large value (e.g. 999.99 dB) to produce accurate results.
To take the characteristics of the filter into account, in the Loss Settings dialog box, enter the insertion
loss of the filter at the RF frequency. To consider the actual filter suppression at the image frequency,
do not enter 999 dB but the actual attenuation for the image rejection.
Measurement on a harmonics mixer
For a harmonics mixer, the input signals are not only converted to the IF by the wanted harmonic, but
also by the harmonic of the LO signal produced in the mixer. In many cases, the mixer even features a
lower conversion loss in the case of unwanted harmonics. For measurements on this type of mixer, a
bandpass filter must be used to make sure that that there is only noise at the desired input frequency at
the input of the DUT. This measurement is similar to measurements on a mixer with an average
sideband suppression.
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