What Is Spurious Emissions — RED?
Unwanted emissions measurement is the measurement in which the emissions emitted by the transmitter outside the operating band, including harmonics and other unwanted components, are scanned in a wide frequency range and compared with limit values.
Purpose of Spurious Emissions — RED
The purpose is to verify that the device will not cause interference to other radio services.
Which Products Is Spurious Emissions — RED Applied To?
- All radio transmitters
- Short range devices
- Cellular and WLAN modules
- Radar and detection devices
In Which Sectors Is Spurious Emissions — RED Used?
Standards Related to Spurious Emissions — RED
- REDEU radio equipment directive test
- ETSIEuropean telecommunications standards test
- FCCUS radio and EMC regulations test
Spurious Emissions — RED Conditions
- Scan range
- Defined in the standard; usually from 30 MHz to the higher harmonics of the carrier
- Measurement settings
- Resolution bandwidth and detector defined in the standard
- Measurement type
- Conductive and/or radiating
- Cihaz durumu
- Both transmitting and standby states are scanned
Equipment for Spurious Emissions — RED
- Semi-anechoic chamber and calibrated antenna set
- Wideband spectrum analyzer/EMI receiver
- Preamplifier and bandpass filters
- Calibrated cable and attenuator set
Sample Requirements for Spurious Emissions — RED
- The device must be in maximum power and worst case configuration
- Cable placement affects the measurement result; must be documented
- Antenna orientations and polarization should be scanned
- Standby status should also be measured
Duration of Spurious Emissions — RED
Typically 1–2 weeks depending on scan interval.
Spurious Emissions — RED Procedure
- 1The device is put into transmission mode.
- 2The defined range is scanned by pre-scanning.
- 3Maximum searches are performed for prominent emissions.
- 4It is measured by optimizing antenna orientation and polarization.
- 5The standby status is scanned.
- 6Results are compared with the limits.
Spurious Emissions — RED Acceptance Criteria
Acceptance criteria are the unwanted broadcast limits given according to the frequency band in the applied standard.
Evaluation of Results
If the maximum search step is skipped by pre-scanning, the worst-case emission may be missed. Limits in receiver bands (guard bands) are generally stricter and are evaluated separately.
Spurious Emissions — RED Report
- Standard applied
- Scanning range and measurement settings
- Device configuration and cable placement
- Emission levels and limits
- Measurement uncertainty
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Radio Equipment Directive 2014/53/EU (RED)
- FCC Part 15
RF and Wireless Testing — What Does This Testing Field Cover?
The section below describes the field that the Spurious Emissions test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
RF and wireless testing shows that a device containing a radio uses the spectrum correctly and operates within the limits the relevant legislation allows. This family is a separate body of work from EMC: EMC addresses unwanted interference, whereas here INTENTIONAL emission is assessed.
Spectrum is a public and limited resource, and this determines the legal character of the field. A device spilling outside its permitted band or emitting excess power is not merely a technical defect but a violation that disrupts someone else's service. Radio conformity is therefore policed more strictly than other test fields and markets maintain their own national regimes.
Measurements run separately on the transmitter and receiver sides. On the transmitter side, output power, occupied bandwidth, frequency error, unwanted emissions, adjacent channel power and the power envelope are measured. On the receiver side, sensitivity, selectivity, blocking and spurious response rejection are assessed. The receiver side is often neglected, but in some bands it is a regulatory requirement.
Access protocol specific behaviours are a third axis: listen before talk (LBT), duty cycle, dynamic frequency selection (DFS) and transmit power control (TPC). These mechanisms enable spectrum sharing and it must be shown that they work correctly.
HUMAN EXPOSURE is the fourth axis and one of the most commercially critical. For devices used close to the body, SAR (specific absorption rate) is measured; for devices used at a distance, a field strength assessment is made. Limits and measurement methods vary by market; the same device is assessed separately for Europe and the United States.
Market regimes are decisive in this family and do not substitute for one another: the Radio Equipment Directive and ETSI harmonised standards in Europe, FCC authorisation in the United States (through a TCB for intentional radiators), ISED in Canada, MIC in Japan, KC in South Korea and SRRC in China each carry their own set of requirements. The same device requires a separate file for each market, and some markets impose a local representative or local testing requirement.
Module integration is the subject that raises the most questions in the field. Using a certified radio module does not automatically make the device compliant. A module certificate is valid for a defined antenna, a defined supply and defined conditions of use; if the antenna changes, the layout changes or the module is operated at a different power level, reassessment is required.
The presence of several radios in the same device (Wi-Fi + Bluetooth + cellular + NFC) gives rise to a simultaneous transmission assessment: SAR and unwanted emission measurements are made for the worst case in which the radios operate together.
Method groups in this field
Transmitter measurements
Output power, occupied bandwidth, frequency error, unwanted emissions, adjacent channel power, power spectral density.
Receiver measurements
Sensitivity, selectivity, blocking, spurious response rejection.
Spectrum sharing mechanisms
Verification of listen before talk, duty cycle, dynamic frequency selection and transmit power control.
Human exposure
SAR measurement (handheld and body-worn devices), field strength assessment, multi-radio scenarios.
Protocol conformity
Cellular network conformity testing, Bluetooth and Wi-Fi certification testing, GNSS performance.
Antenna measurements
Gain, radiation pattern, efficiency and total radiated power (TRP) measurements.
Commonly confused in this field
- Using a certified module does not automatically make the device compliant; if the antenna, layout or power level changes, reassessment is required.
- An FCC file does not replace a CE file; each market operates its own regime.
- Receiver side measurements are a regulatory requirement in some bands; measuring only the transmitter produces an incomplete file.
- SAR limits and measurement methods differ by market; a result in one market does not carry over to another.
- For devices carrying several radios the simultaneous transmission scenario must be assessed; measuring them individually is not sufficient.
- Some markets impose local testing or a local representative requirement; technical conformity alone does not secure market access.
Which decisions these results support
- Market access under radio equipment legislation
- Verification of the antenna and RF front end design
- SAR and RF exposure conformity
- Verification of module integration and the scope of reassessment
- Determining the worst case in multi-radio scenarios
Related Tests
Frequently Asked Questions About Spurious Emissions — RED
According to which standard is Spurious Emissions made?
Spurious Emissions is executed in scope Unwanted broadcast sections of ETSI radio standards, FCC Part 15, CISPR 16-1-1, ERC/REC 74-01 (unsolicited broadcast limits), RED, ETSI and FCC. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Spurious Emissions apply to?
Mainly applied to All radio transmitters, Short range devices, Cellular and WLAN modules and Radar and detection devices. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Spurious Emissions done?
The determining parameters are: Scan range — Defined in the standard; usually from 30 MHz to the higher harmonics of the carrier, Measurement settings — Resolution bandwidth and detector defined in the standard and Measurement type — Conductive and/or radiating. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Spurious Emissions?
The device must be in maximum power and worst case configuration, Cable placement affects the measurement result; must be documented and Antenna orientations and polarization should be scanned. The number of samples is determined according to the product standard and the scope to be reported.
How long does Spurious Emissions take?
Typically 1–2 weeks depending on scan interval. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Spurious Emissions result called "appropriate"?
Acceptance criteria are the unwanted broadcast limits given according to the frequency band in the applied standard.