Jan, The digital device can be tested as a Class A device, but the transmitter can not, as 15.225 requires testing to the limits of 15.209 for an intentional radiator. One key element here is to recognize the the frequency range for which the digital device must be tested is 150kHz to 30 MHz ac line conducted, and 30 MHz to 1000 MHz radiated (possibly higher depending on the highest clock/timing signal in the device). The transmitter has to be tested from the lowest radio frequency signal generated in the device (no lower than 9kHz), up to at least the 10th harmonic of the highest fundamental frequency of the transmitter. In your case, approximately 136 MHz. See FCC Part 15.33 for further clarification. The emissions from the digital device should be compared the the Class B limits, and those emissions from the radio transmitter should be compared tot he 15.209 limit. The devices both have to be tested as a system, unless you chose to request a Modular Approval for the transmitter. I hope this helps. Regards, William M Stumpf DLS Electronics 166 South Carter St. Genoa City WI 53128 ph: 262-279-0210 fx: 262-279-3630 email: [email protected]
From: Jan Vercammen [mailto:[email protected]] Sent: Wednesday, March 10, 2004 8:04 AM To: [email protected] Subject: question concerning FCC Subparts B/C __________________ Hello emc-pstc list, I have a question concerning the integration of an RF tag reader or Short-Range-Device operating in the 13,56MHz band in a medical printer. In order to understand the full issue one needs complete product information. It concerns a medical printer, that is, a printer that is is used in hospitals, healthcare centers and possible at residential areas. For residential areas the printer operation is by a healthcare specialist (e.g. radiologist that operates his own radiology business, but these cases are limited). The printer is not portable (weight 75kg), but it is a model. The printer is a complex machine that provides: - a twisted-pair LAN (Ethernet) interface - queueing and storage for images - image processing - manages many sensors, DC and stepper motors and electromagnetic clutches for film transport - and a wirelessshort range RF system for the identification of the film type (batch nr, film type, film processing data, ...) The RF device operates at 13.56MHz and is a small printed circuit board (PCB) of 11cmx7cm. The antenna is integrated on the PCB (and is not removable). The interface to the printer is over a RS232 interface. The RF tag reader is mounted in the film input cassette and is positioned to align the tag in the film pack with the antenna of the reader. The maxiumum power of the RF device is 100mW( and, by means of a relay, 10mW for Japan). The RF reader is part of the printer, it is just a module. >From a regulatory point of view we have Europ. The printer + RF device is tested according to IEC60601-1-2:1993, class A for emissions. The RF device is tested according to ETSI (EN) standards. Our main focus is now on the US and we need to apply FCC rules. The code of federal regulations part 47 part 15 subpart A (=definitions), B (=unintentional radiators) and C (=intentional radiators). I reference the FCC standard clause 15.3 (K), which concerns the definition of a digital device. It states somewhere halfway: A radio frequency device that is specifically subject to an emanation requirement in any other FCC Rule part or an intentional radiator subject to subpart C of this part that contains a digital device is not subject to the standards for digital devices, provided the digital device is used only to enable operation of radio frequency devicea nd the digital device does not control additional functions or capibilities. In this case the digital device is the printer and the main operation is that of a printing device. The RF device is a small internal part. The digital device (= the printer electronics) has many more functions and control functions besides controlling the operation of the RF device and therefor it seems to qualify (?) as a digital device. The RF device should be tested according to clause 15.225 of part 47 part 15 subpart C, which has details about the testing of the radio parameters of RF devices operating in the band 13.553-15.567MHz. The printer with the RF device should comply with emission limits of part 47 subpart B class A or B. If one follows the classification then one can use class A. The above, however, is my line of reasoning. It has a focus on the fact that the printer is a commercial non-portable digital device, which happens to include a RF device of which the radio type parameters have been tested. However, there is an alternative line of reasoning: by including an RF device, which requires class B emisison limits (see clauses 15.207 & 15.209), the whole printer becomes a class B device. However, the class B limits are for intentional radiators and not for digital devices! The question is simple: can we use class A emission limits for the printer + RF tag reader? If we can not, what are the arguments why class A can not be used? I hope that you can help me to figure this one out. Kind regards, Jan Vercammen EMC engineer I have asked the RF device maufacturer and the maintain that the device should be tested as Kind regards, Jan Vercammen Agfa-Gevaert NV, Belgium
