They are not the same Dennis Ward ATCB

The FCC has a requirement that Applications for certification through the TCB program must contain test reports that CLEARLY show testing was performed in accordance with established approved FCC procedures. The FCC has recently shown concern that proper test procedures and methods are not being done or followed. Procedures for Licensed and unlicensed devices are not the same. Some devices do not have established procedures.

A lab may be proficient in part 15 unlicensed intentional radiators but this does not mean the lab is proficient in testing licensed transmitters. The same may be true the other way round. The lab should thoroughly understand the rule part, test methods and procedures it will be using. The lab must also clearly identify these established procedures in the test report.

–Typically the approved procedure is to be referenced in the report and subsequent test methods clearly stated for each test type. Power, radiated emissions, conducted antenna terminal, occupied bandwidth each should provide clear and related test methodology in accordance with the approved standard. Typically for licensed devices this is TIA603C. Most part 15 devices use ANSI C , and others for example are not tested to ANSI C63.4.

The Obvious differences Test procedures and requirements for the licensed world include: –A world of power –A world of modulation –A world of protected services The test procedures and requirements for the unlicensed world include: –With a few exceptions a world of field strength. –Has no protection for an unlicensed transmitter. –Not allowed to interfere with a licensed service. –Subject to many restrictions.

Testing Differences The licensed world of TIA603 –Licensed devices are devices whose outputs are conducted power at the antenna terminal or ERP/EIRP oriented. Antenna terminal conducted power measurements for devices with removable antennae. ERP/EIRP measurements in accordance with TIA603 (not reverse calculated field strengths) for devices with non-removable antennae. Because of higher power levels and modulation measurement requirements, labs must have appropriate test equipment (appropriate attenuators etc). Labs must be well versed in TIA603 as well as the use of this specialized equipment.

Testing Differences contd –Modulation must be appropriate for the licensed service. Labs must have and be able to adequately use appropriate modulation analyzers, base station simulators, etc. to analyze the modulation characteristics of the transmitter. Emissions designators must be adequately addressed. Lab personnel must be able to determine proper emissions designators

Testing Differences contd –Measurement techniques are generally well defined by TIA (TIA 603-C 2004). –The lab must be very familiar with the licensed device test methods under this standard and must be able to determine what test procedure is appropriate. –The lab must be able to associate what test methods do or do not apply and when 47CFR stipulations take precedence. –Labs must follow the applicable portions of TIA603 dealing with the device tested. –Labs must know when TIA603 does not apply and where (i.e. how or where does TIA603 apply to part 90Y, part 27 AWS etc)

Testing Differences contd –The lab must understand and be able to perform proper testing in accordance with TIA603 for: Conducted antenna carrier output. Temperature and voltage frequency stability. Modulation limiting. Carrier attack time and transient frequency behavior. Adjacent channel power. Audio sensitivity, distortion and frequency response. Audio low pass filter response Intermodulation Antenna substitution measurements. –The FCC requires this to be a measured value and not a calculated equivalent field strength. –Example - What methods from TIA 603 apply to the transmitter fundamental and which apply to the spurious. –The lab must know and understand the difference. The lab must finally adequately explain how and why a particular test was performed and include this explanation in the test report.

Testing Differences contd The unlicensed world –Testing is done in strict accordance with approved test procedures. –As applicable, testing is also done in accordance with ANSI C63.4 –Testing is done on a approved OATS (except for antenna term measurements). Labs that are only listed on the FCC site are not exempt from establishing/showing confidence in their ability to test. Labs accredited and shown on the FCC site, while having a presumption of competence, must/should still establish/show confidence in their ability to test.

Testing Differences contd The lab must understand, be able to perform and show competence in proper testing in accordance with ANSI C63.4 and any specific intentional radiator test procedures including: –DA FHSS systems. –Measurement of Digital Transmission Systems Operating under Section (3-2005). –mm wave devices The lab must understand how to convert field strength levels to ERP/EIRP. –Unlike the licensed world, this can be a calculated ERP. –The lab can use measured ERP instead of calculated for the unlicensed world – but not the other way round) The lab must understand and know how to incorporate appropriate Pulse Desensitization techniques when necessary. –HP/Agilent Technical note 150 is a good start. The lab must clearly explain how testing performed.

Questions