Managing Dual Band Radio Laboratory Testing under Chinese Regulatory Frameworks
SRRC approval for dual-band radios demands locked firmware power tables, local agent coordination, and strict host radiated spur compliance to avoid re-test delays.
Intermodulation Spur Levels
Meaning
Wireless signal distortion metrics measure the unwanted signals generated when two or more frequencies interact in a non-linear component or system. The intermodulation spur levels define the amplitude of these unwanted mixing products relative to the carrier signal or in absolute power units. Keeping these spurious emissions below specified thresholds is necessary to prevent interference with adjacent frequency bands and to comply with regulatory standards.
Source Analysis
Non-linearities in the power amplifier or passive components like connectors can generate these unwanted frequencies. When multiple signals are transmitted simultaneously, or when a strong external signal enters the transmitter chain, mixing occurs. The resulting signals can fall into bands assigned to other wireless services.
Filtering Strategy
Bandpass filters placed after the amplification stage attenuate these out-of-band emissions before they reach the antenna. The filter design must balance insertion loss against the attenuation required to meet the spurious emission limits. Designers must carefully select these components during the hardware development phase.
Laboratory Evaluation
Testing laboratories use spectrum analyzers to measure the power of these spurs during the transmitter compliance evaluation. The measurements are performed across a wide frequency range to ensure that no harmful emissions are present. This step is a prerequisite for system certification.