Class 1

EN 300 220-1 & Class 1 Receiver compliance

Article by Timothy Last, Applications Engineer, July 2009

 

NRX2 imageClass 1 receiver performance continues to be a hot topic: Despite delays and amendments to the anticipated new version of EN 300 220-1 Radiometrix modules continue to be well specified to meet forthcoming regulations for wireless Short Range Device usage in critical applications.

 

What is “Receiver category 1”?

“Highly reliable SRD communication media; e.g. serving human life inherent systems (may result in a physical risk to a person).” In other words (as far as radio modules are concerned), it applies to any module containing a receiver to be used in an application where physical risk to people would result from substandard performance. There are also two further categories concerned with SRDs and further information regarding categories, performance and testing is available on our website: http://www.radiometrix.com/test-your-receiver.

 

It is the responsibility of the manufacturer (of the equipment into which a RF module is being incorporated) to choose and declare the category applicable to the equipment in question. This should directly influence the type of module being chosen by the equipment manufacturer. The information is also incorporated into product literature for the equipment.

 

The latest news from Europe

 

Class 1, or category 1 receiver performance continues to be a hot topic. The proposed replacement for European standard EN 300 220 version 2.1.1, which was recognised to be a potential “show stopper” for many high performance Short Range Device (SRD) otherwise well suited to safety critical applications was intended to have been published by February 2009. This would have been finalised as version 2.2.1.

Instead, the European Telecommunications Standards Institute Technical Body (ETSI TB) responsible for reviewing the proposed standard after a period of Public Enquiry, took approximately half a year (instead of the anticipated two months) and made some changes that have resulted in version 2.3.1, itself now subject to a further Public Enquiry, which should conclude by the end of July 2009. Another review period will follow (scheduled two month duration), followed by a vote (which takes two months) and after that? Well “it should all be over by Christmas”. Unless the process is repeated, I suppose.

Incidentally, the phrase “Public Enquiry” can be misunderstood. “Public” in this instance means representation to ETSI by a National Standards Organisation (NSO). For example in the UK this would be BSI British Standards. If you ask at ETSI where the Public Enquiry is being held and how to be a part of it (as I did) you will be politely directed to your local NSO.

So after six months of reviewing and revisions this new version 2.3.1 must be quite different to the previous one then? From a quick read-through there is more detail and clarification for Listen Before Transmit (LBT) systems and also the complete removal of a section dealing with Transient Power (power falling into adjacent spectrum due to switching the transmitter on and off during normal operation). Hmmm – new potential sources of detrimental interference there then. One wonders why that section was removed?

 

Class 1 receivers

 

Anyway, all very interesting (ahem), “but what about Class 1 receivers?” I hear you ask. No I haven’t enticed you to read my article under false pretext; there is change but the good news is that it is not a “show stopper” for the numerous modules that Radiometrix can offer the designer of a system using wireless SRDs requiring compliance with Class 1: the spurious response rejection tests, absent in version 2.2.1, are back in the latest proposed version.

 

Spurious responses

 

The spurious response rejection performance of a receiver reveals how much effort has been put into rejecting those unwanted signals to which a design is inherently vulnerable. The relationships between Local Oscillator(s) and Intermediate Frequencies in a typical receiver design result in vulnerabilities whereby a signal on an “image frequency” can produce a response in the receiver as if that signal was on the wanted
frequency. Low cost designs usually contain lower component counts and lower cost components. Sometimes a crude SRD receiver will respond to an image signal almost as well as a wanted signal. So this re-introduction of an important aspect of receiver performance should be welcomed when dealing with safety critical applications.

 

Q: Which modules can I use?

 

Here are some hyperlinks to narrowband Radiometrix modules that can be incorporated into equipment needing a receiver intended to meet forthcoming requirements for receiver category 1. For specific module features & recommendations the reader is encouraged to examine the individual datasheets.

 

VHF

  • LMR1-173-5 Low cost multi-channel receiver: 173MHz (UK only) frequencies

  • TR1M-169-5 Multi-channel transceiver: 169MHz (EU - social alarms) or 173MHz (UK only)

 

UHF

  • NRX2-434.650-10 Single-channel receiver: 434MHz EU or 458MHz (UK only) frequencies

  • NiM2-434.650-10 Single-channel transceiver: 434MHz EU frequencies

  • NTR2-434.650-10 Single-channel transceiver: 434MHz EU or 458MHz (UK only) frequencies

  • LMR2-433-5 Low cost multi-channel receiver: 434MHz EU or 458MHz (UK only) frequencies

  • RX2M-4xx-5 Multi-channel receiver: 434MHz EU or 458MHz (UK only) frequencies

  • USX2-433-5 Multi-channel transceiver 434MHz EU or 458MHz (UK only) frequencies

  • TR2M-4xx-5 Multi-channel transceiver 434MHz EU or 458MHz (UK only) frequencies

  • TR3M-869-5 Multi-channel transceiver 868MHz EU frequencies

 

It is also worth mentioning that there is no reason to deliberately use a lower performance module just because the usage does not fall into the class 1 category. It may simply be that the best module fit for the application also happens to meet the performance requirements of receivers in category 1.

 

Q: Why should I bother with any of this?

 

If the intention is to sell equipment in the UK, or elsewhere within the European Union, the equipment manufacturer is responsible for ensuring that the equipment meets the standards agreed and adopted by the EU member states. The EN 300 220 standards proposed and coordinated by ETSI are the ones adopted throughout the European Union applicable to wireless SRDs. When applying the CE mark, the manufacturer is declaring responsibility: stating that equipment meets applicable EU standards. This is what should be considered when incorporating radio modules into equipment destined to form part of a “human life inherent system” for sale within the EU.

Further reading is also available here: http://www.radiometrix.com/files/additional/Letter-of-the-Law.pdf

 

For more information, please contact our sales team.

 

 

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Limitation of liability The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd reserves the right to make changes or improvements in the design, specification or manufacture of its subassembly products without notice. Radiometrix Ltd does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. This data sheet neither states nor implies warranty of any kind, including fitness for any particular application. Radio devices may be subject to radio interference and may not function as intended if interference is present. We do NOT recommend their use for life critical applications. The Intrastat commodity code for all our modules is: 8542 6000

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