Host Level Radiated Spurious Emission Pre Scan Chamber Verification Protocol
Host level pre scan verification systematically isolates host radiated spurious noise before accredited certification testing to prevent market entry delays.
Receiver Gain Compression
Meaning
Non-linear behaviors that occur in amplification stages when the input signal power exceeds the linear range of the device limit the accuracy of electromagnetic sweeps. In electromagnetic compatibility testing, receiver gain compression occurs when a strong signal reduces the receiver’s gain, causing weaker signals to be measured below their true values. This effect can distort the emission profile and lead to incorrect compliance decisions.
Limit Condition
The one decibel compression point defines the threshold where the amplifier gain drops by one decibel from its small-signal value. If the input signal pushes the receiver into receiver gain compression, the measured spectrum will show false peaks and distorted amplitudes. Engineers must monitor signal levels to ensure the system operates within its linear region.
Signal Distortion
Overloading the input stage of the analyzer generates internal harmonics and intermodulation products. These spurious signals can be mistaken for actual emissions from the device under test.
Prevention Method
Step attenuators are used to reduce the signal level entering the receiver and restore linear operation. During the pre-scan phase, the operator can increase the input attenuation by ten decibels to check for compression. If the measured signal level does not change by the same amount, the receiver is in compression.
In this scenario, additional external attenuation is required to ensure accurate measurements.