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Radiated field correction worksheet

Start with the measurement being performed

Conducted-voltage, radiated-field and current-probe measurements use different transducers and reporting units. Identify the port or field component, frequency range and test arrangement before opening a limit file. The quantity on the display may already include some or all correction factors.

The worksheet on this page is specifically for a receiver voltage in 诲叠碌痴 combined with an antenna factor in dB/m. It produces a field-strength result in 诲叠碌痴/m. Do not insert a current-probe transfer impedance into that field and label the resulting arithmetic as a radiated electric-field measurement.

Radiated-field correction chain

Understand what the detector changes

Peak detection emphasizes the largest observed amplitude, while average and quasi-peak processing respond differently to the signal's time behavior. The correct detector is established by the actual test method. A fast peak scan can support screening, but its result cannot be relabeled as quasi-peak by subtracting a fixed number.

Pulsed and intermittent disturbances make observation time important. Record dwell or measurement time together with the detector. The operating mode must remain representative during that interval; an emission that occurs only when a motor starts or data traffic bursts can be missed by an unsuitable sequence.

Keep bandwidth and scan settings visible

Resolution bandwidth changes how the instrument collects energy from a signal. The required filter definition and bandwidth belong with the test method, not with whichever analyzer preset gives a clean-looking trace. Frequency stepping and observation time must also be sufficient to find the disturbance of interest.

Preserve the instrument configuration with the data. Two traces taken with different settings may support a diagnostic hypothesis, but are not automatically a before-and-after performance comparison. State which variables changed, including attenuation, preselection, preamplifier use and sweep strategy.

Correct the full radiated measurement chain

For the simplified chain here, corrected field=receiver reading+antenna factor+cable loss鈭抏xternal amplifier gain. All terms must correspond to the same frequency and configuration. The gain term applies only to an external contribution that has not already been removed by instrument correction.

For example,40诲叠碌痴 plus20dB/m antenna factor plus2dB cable loss minus20dB amplifier gain gives42诲叠碌痴/m. Against an entered46诲叠碌痴/m limit, the arithmetic margin is 4dB. This is not an uncertainty-adjusted compliance decision, and the example is not a universal product limit.

Avoid double correction and hidden clipping

Before applying factors, check whether the receiver software already uses a transducer table. Applying the same antenna factor twice can create a large error while every individual number appears reasonable. Confirm cable and amplifier identifiers against the actual connected hardware and calibration records.

Also check overload and noise floor. A strong out-of-band signal can compromise a reading, and a very low trace can be limited by the measurement chain rather than the product. More displayed digits cannot recover information lost to clipping, saturation or insufficient sensitivity.

Match the limit to the test conditions

A limit belongs to a particular product category, detector, bandwidth, distance and configuration. Do not compare a convenient bench reading directly with a chamber limit whose setup is different. The worksheet requires you to supply the applicable limit and deliberately makes no claim that the selected value is legally sufficient.

Measurement uncertainty and the applicable decision rule need separate treatment. A positive arithmetic margin is useful for engineering prioritization, but the lab's accepted procedure determines how the final result is reported. Retain that procedure with the test report rather than inventing a universal margin requirement.

Use the receiver to test a hypothesis

Compare a baseline with a controlled change while holding the setup and operating mode constant. A temporary cable ferrite, alternate bonding route or disabled clock can help isolate a mechanism, but the diagnostic modification is not necessarily a producible fix. A change can reduce one peak and expose another.

The board and enclosure EMC guide connects these observations to cable exits, seams and return paths. Correlate receiver data with the physical system instead of treating the loudest board location as proof that it is the sole source of the product's radiation.

Prepare a useful handoff

Save hardware and software revisions, photos of the setup, cable arrangements, instrument settings, correction files, detector and uncertainty information. Include the relevant operating state and the specific failed or marginal frequency regions. These details make an engineering review repeatable and help avoid rebuilding a fixture from memory.

If a PCB or assembly change follows, update the released drawing and BOM as well as the test record. For a 吃瓜tv enquiry, identify the manufacturable change and the evidence it is intended to preserve. Downloaded worksheet text remains local and must be attached manually; no measurement file is uploaded or interpreted by this page.

Preserve the measurement chain

Record the actual instrument and accessory configuration alongside the trace. Include calibration references, detector, bandwidth, observation time, input attenuation and external gain. A result without these settings may be impossible to compare fairly with a later test.

Identify which corrections have already been applied by software. Keep raw and corrected data distinguishable, with units attached to each. A correction factor belongs to a particular transducer and frequency; a similar-looking table from another setup is not a substitute.

When comparing a result with a limit, verify the product category, test geometry, detector and reporting convention. Retain uncertainty and the accepted decision rule separately from a simple arithmetic margin. Engineering screening can guide the next experiment without being presented as a formal compliance report.

Turn the design decision into a controlled record. Keep the schematic and layout revision, model source, operating case and requirement together. Distinguish an entered assumption from a supplier nominal value and a measured result. If an important value is missing, record the unresolved question rather than replacing it with a convenient typical number.

Compare alternatives at a consistent boundary. Preserve the baseline and change one relevant variable when possible. If several features change together, describe the outcome as a comparison between configurations; do not assign the entire improvement to the one component you wanted to justify. Keep both favorable and unfavorable frequency regions in the evidence.

Before a repeat order, check whether substitutions affect the reasoning. A package change, alternate dielectric, shield finish or assembly operation can invalidate an earlier comparison even when the visible board outline is unchanged. Specify which changes need engineering review and which are already accepted. This makes the purchasing and manufacturing handoff useful without asking either team to reconstruct the original electrical investigation.