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Dormer M.,Radiometrix Ltd.
Electronics World | Year: 2010

Myk Dormer, Senior RF Design Engineer at Radiometrix Ltd. defines the global recession or the credit crunch on the low power wireless market. The generally weak linkage between this industry area and the financial/consumer sectors provided a degree of insulation. While the market for low power wireless devices has not completely collapsed, order levels are down and scheduled or repeat orders are being postponed, delayed or canceled. This, in turn, has reduced the immediate income of what are in this industry area generally small-to-medium sized manufacturers, forcing economies in both staffing and capital investment. While the current depressed state seems fairly stable as the market begins to reinstate and order levels rise, there are a few effects that must be watched. The industry must minimize the long term damage caused by external conditions and directives, by using part time working. Customers should anticipate longer than usual lead times.


Dormer M.,Radiometrix Ltd.
Electronics World | Year: 2010

Techniques employed for the increased sensitivity of ISM band radio modules are discussed. A reference link is established using a simple biphase remote control chipset (CTR44, operating at 1kbit/s) and a -120dBm sensitivity receiver. Reliable signaling is observed at -122dBm signal level while halving the data speed yields a 2dB gain in performance. A simple modification is made to the receiver, connecting the data extractor to the RSSI output instead of the discriminator, which results in a simple OOK receiver. The improvised receiver at 250bit/s could reliably operate at -125dBm, while a 30 bit per second test responds at -127dBm, although the response time of the system is several seconds. The use of squarewave modulation waveforms at very low modulation frequencies, where the deviation is several orders of magnitude greater than the baseband rate ensures that the spectrum of an FM signal resolves to a pair of carriers, at ±F(dev).


Dormer M.,Radiometrix Ltd.
Electronics World | Year: 2010

Myk Dormer, Senior RF design engineer at Radiometrix Limited shares his views on the engineering. According to him, financial organizations that can see beyond the next month's profit figures and who can understand the need for a company to invest in its future. Suppliers who manufacture sufficient numbers of their products for the demands of their market, so shortages and allocations are occasional accidents, rather than a regularly used technique to hold artificially high prices and excuse long lead-times. Sales and marketing executives who treat a new design as a new possibility for valuable new orders, rather than looking on it as an attack on their self-created, comfy, well-ordered, artificial, little worlds. A reliable, easy to use desktop computer which, when replaced by a model with twice the memory and four times the processing newer.


Dormer M.,Radiometrix Ltd.
Electronics World | Year: 2010

Myk Dormer, Senior BE Design Engineer, Radiometrix Limited, shares his views on the low data rate transmission. A given module is capable of transmitting a 128kbit/s data stream then it is inherently superior to a unit operating at, such as 5kbit/s. For radio links, in the simplest sense, data rate, transmit power and operating range constitute three competing factors within which the design must find a compromise. Short range radio modules offer 64kbit/s or higher data speed while large, expensive radio modems increase transmitter power to push 5 to 10 kbaud data streams 5km or more. Basic communications theory predicts a 3dB improvement in S/N (and hence signaling sensitivity) with each halving of the signal bandwidth. A basic data communication link, typical of simple ISM band practice, was assembled. A simple program running on the lab PC generates (and displays) a constant sequence of eight byte test transmissions.


Fog

Dormer M.,Radiometrix Ltd.
Electronics World | Year: 2012

Any electronic system using non-steady state signals will, by definition, radiate wide-band noise, covering tens or hundreds of MHz. This 'radio frequency effluent' is usually within the legal RFI limits for the device, leaving no recourse to complain to its supplier or the regulatory bodies, but is still more than sufficient to noticeably de-sense any radio link located within a couple of meters of the device. Identifying this form of interference is quite easy, once you know what to look for. It is rarely possible to see such signals on spectrum analyzer/wide-band aerial setups so elimination tests are the best way forward: A typical narrowband receiver might have a working sensitivity of -120dBm. Assemble a 'range comparison trial' prototype, using the same radio link, data structures and aerial but without the customer's digital hardware.

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