Meaning
Form of signal distortion characterized by the creation of new frequency components when multiple signals pass through a non-linear system under transient conditions. High speed communication systems experience dynamic intermodulation when the power levels of the input signals change rapidly. The phenomenon degrades the signal to noise ratio and can lead to bit errors in wireless data links.
Signal Integrity
Non-linearities in the power amplifier or the mixing stage cause the generation of unwanted sidebands. While static tests might show clean results, dynamic intermodulation appears only when the modulation envelope is active. Fast rising edges in a digital signal are particularly susceptible to this type of degradation.
Testing Protocol
Interference from these spurious signals can bleed into adjacent frequency channels and violate spectral masks. Excessive dynamic intermodulation necessitates a reduction in the total output power or the use of more linear components. Engineers often implement digital pre-distortion to counteract the predictable elements of this distortion.
The use of adaptive algorithms helps maintain performance as the operating temperature and voltage fluctuate.
Mitigation Barrier
Linearity is measured by comparing the power of the third order products to the power of the fundamental signals. Because dynamic intermodulation is sensitive to the rate of change, testing involves using two or more tones with varying amplitudes. A system with high linearity maintains a wide dynamic range even under heavy traffic loads.
