Test Equipment & Facilities Requirements Flashcards
6 cards from real FCC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Test Equipment & Facilities Requirements flashcards as text
What is the 'noise floor' of an EMI receiver and why does it matter for FCC testing?
Answer: The lowest signal level the receiver can detect; emissions below the noise floor cannot be measured, so a low noise floor is essential for testing near the emission limit
The noise floor is the minimum signal level measurable by the receiver; if the emission limit is close to or below the receiver's noise floor, the measurement system cannot determine whether the device complies, making low-noise receivers and preamplifiers essential.
What is the purpose of performing a 'site VSWR' or 'normalized site attenuation' (NSA) measurement for chamber validation?
Answer: To confirm that the test site provides propagation conditions within ±4 dB of theoretical free space, validating it as a suitable substitute for an OATS
NSA measurement validates that the chamber's measurement environment replicates free-space propagation conditions closely enough for accurate emissions testing, confirming the site can be used as an alternative to an OATS for FCC compliance testing.
What is the role of a 'coaxial cable' in an FCC radiated emissions test setup, and what parameter must be characterized?
Answer: To connect the receive antenna to the EMI receiver; its insertion loss (attenuation) must be measured and subtracted from measurement results
The coaxial cable carries the received signal from the antenna to the measurement receiver, and its frequency-dependent insertion loss must be measured and used as a correction factor to account for signal attenuation in the overall measurement equation.
What is a 'reverberation chamber' and for what FCC testing applications might it be used?
Answer: A shielded room with mode-stirrers to create a statistically uniform, isotropic field environment, used for radiated immunity testing and total radiated power (TRP) measurements
A reverberation chamber uses mechanical or electronic stirrers to create a reverberant multipath environment with statistically uniform field distribution, suitable for radiated immunity testing and measuring total radiated power and total isotropic sensitivity of wireless devices.
What test equipment maintenance record must an FCC accredited laboratory maintain for all measurement instruments?
Answer: Calibration records showing calibration date, results, calibration status, and next calibration due date, with traceability to national standards
ISO/IEC 17025 requires laboratories to maintain calibration records for all equipment affecting measurement results, including the calibration date, outcome, calibration status indicator, and scheduled recalibration date, ensuring traceability is maintained.
What is the purpose of a 'phantom' or human body simulator in SAR (Specific Absorption Rate) testing for FCC certification?
Answer: To simulate the human body's dielectric properties so that RF absorption in tissue can be measured when a device is held close to the body
The SAR phantom is a shell shaped like the human head or body, filled with a tissue-simulating liquid whose dielectric properties match human tissue at the test frequency, allowing measurement of the electric field (and hence absorbed power) inside the simulated body.