incidental FM
Undesired frequency modulation on the output of a device (for example a signal source or an amplifier) caused by or, incidental to, some other form of modulation, such as amplitude modulation.
input attenuator
An attenuator between the input connector and the first mixer of an analyzer (also called an RF attenuator), The input attenuator is used to adjust the signal level incident to the first mixer, and to prevent gain compression due to
then changes the reference level accordingly. In
input impedance
The terminating impedance that the analyzer presents to the signal source. The nominal impedance for RF and microwave analyzers is usually 5062. For some systems, such as cable TV, 750 is standard. The degree of mismatch between the nominal and actual input impedance is called the VSWR (voltage standing wave ratio).
interface
The point at which different parts of a system interact. Also, the point at which operators and instruments interact.
intermodulation distortion
Undesired frequency components resulting from the interaction of two or more spectral components passing through a device having nonlinear behavior, such as a mixer or an amplifier. The undesired components are related to the fundamental components by sums and differences of the fundamentals and various harmonics. The algorithm is:
fl~f2,2xfl~f2,2xf2ff~,3Xf~f2xf2, andsoon
