Licensed verses Unlicensed

1. Licensed verses Unlicensed • They are not the same • Dennis Ward • ATCB

2. The testing dilemma • 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.

3. The testing delimna • 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.

4. The testing dilemma • 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 C63.4 2003. • 15.247, 15.407 and others for example are not tested to ANSI C63.4.

5. 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.

6. 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.

7. 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

8. 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)

9. 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.

10. 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.

11. 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: • DA000705 FHSS systems. • Measurement of Digital Transmission Systems Operating under Section 15.247(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.

12. Questions