CE Radio Equipment Files a Distributor Can Actually Produce
CE radio compliance files accessible to distributors consist of declarations, user safety manuals, Notified Body certificates, and test summaries.
Unwanted Domain Emissions
Meaning
Radio transmitter outputs must be restricted to their allocated bands to prevent interference with neighboring frequency allocations. Managing unwanted domain emissions involves suppressing spurious and out-of-band signals generated during the modulation or amplification process. This control is necessary to comply with international radio regulations.
Spectral Limit
Regulatory bodies define strict mask limits that specify the maximum allowed power level for any signal outside the allocated channel. These limits become increasingly stringent as the distance from the carrier frequency increases. Transmitters must be designed to meet these limits across all operating modes.
Failure to do so can result in the rejection of the product by certification agencies.
Filter Design
Adding bandpass filters to the RF front-end is the primary method to attenuate these unwanted out-of-band signals before they reach the antenna. These filters must have high selectivity and low insertion loss to preserve the transmitter’s efficiency. They are designed to block harmonics and mixing products while allowing the desired signal to pass.
The design of these filters must be optimized for the specific operating frequencies. This optimization is particularly important in multi-radio devices where co-located antennas can easily be desensitized.
Testing Validation
Testing laboratories measure these emissions using spectrum analyzers during the formal certification process. The transmitter is operated at maximum power while the analyzer scans the surrounding spectrum for non-compliant signals. This validation is a mandatory step to secure market access for any wireless device.