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APPLICATIONS
4-6
Amplifier intermodulation distortion application
Intermodulation tests on amplifiers are a good indication of the linearity of an amplifier. Many
communication systems require devices able to carry two or more signals without introducing
spurious frequencies which might affect system performance. The 2026Q can support 2-tone
intermodulation testing. The number of tones can also be increased by using the external source
input, INPUT FROM RADIO TEST SET, for the connection of external generators.
Two-tone test
In this test two tones are input to an amplifier. Amplifier output will comprise not only the two
applied tones but also, due to amplifier non-linearity, intermodulation products. One tone is
provided from source A at the required amplifier frequency. The second interfering tone is
provided from source B at a different frequency but same amplitude.
Procedure
You can carry out an intermodulation distortion test on an amplifier as follows:
(1) Press
[Amplifier IM]
which displays the
Intermod. Distortion Test
on Amplifier
block
diagram as shown in Fig. 4-5 below.
Fig. 4-5 Intermodulation distortion test on amplifier block diagram
(2) Connect the amplifier under test to the output from the combiner (CONNECTION TO
RADIO socket) as shown by the block diagram.
(3) Press
[Spectral Diagram]
which displays the
Intermod. Distortion Test
on Amplifier
spectral
diagram as shown in Fig. 4-6 below.
Fig. 4-6 Intermodulation distortion test on amplifier spectral diagram