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.
Fundamental Notch Filters
Meaning
Bandstop attenuation devices are integrated into test setups to suppress high power carrier signals before they reach sensitive receivers. When testing for low level harmonics, fundamental notch filters are used to prevent the strong primary signal from causing receiver overload or intermodulation distortion. This attenuation ensures that the measured harmonic levels are generated by the device under test and not by the measurement system itself.
Signal Suppression
High dynamic range measurements require a deep notch of forty decibels or more at the carrier frequency. These fundamental notch filters must maintain low insertion loss at the harmonic frequencies to avoid degrading the sensitivity of the measurement. Cavity filters are often selected for their high power handling and sharp roll-off.
Device Insertion
Placing the filter between the antenna or coupler and the receiver protects the input mixer from damage. This insertion must be accounted for in the system calibration to ensure correct amplitude results.
Laboratory Test
Diagnostic routines verify the notch frequency and depth before each measurement run. Using a network analyzer, the engineer sweeps the filter to confirm it is tuned to the exact frequency of the transmitter under test. If the transmitter frequency drifts, the notch filter must be retuned or replaced to prevent the carrier from leaking through and saturating the receiver.
This verification is a standard step in the transmitter compliance test flow.