  For the characterization of components, systems and signals in the range of
microwave and radio-frequencies (RF) specific equipment and dedicated
measurement instruments are used. In this article the fundamentals of RF signal
processing and measurement techniques are discussed. It gives complementary
background information for the introduction to RF Measurement Techniques and
the Practical RF Course, which are part of the Advanced Accelerator Physics
training program of the CERN Accelerator School (CAS) and have also been
presented at the CAS 2018 Special Topic Course in Beam Instrumentation.
