Product category:
Wireless Communications
News Release from: Hemisphere GPS
Edited by the Electronicstalk Editorial
Team on 07 July 2003
Patent for novel ceramic frequency
filter
CSI Wireless has been awarded a patent on its new ceramic frequency filter for differential GPS (DGPS) correction signals.
CSI Wireless has been awarded a patent on its new ceramic frequency filter for differential GPS (DGPS) correction signals The filter uses a ceramic material, which permits increased sensitivity, better signal acquisition, and less interference than traditional filters using metal inductors
This article was originally published on Electronicstalk on 12 Feb 2002 at 8.00am (UK)
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The ceramic filter is used in all of CSI's beacon receivers, providing high performance across the entire line of receivers.
It comes encased in a single unit for plug-and-play integration - providing a quick, easy, low-cost solution without any tuning requirements.
The patented filter is the key element in CSI Wireless' MBX3 differential GPS receiver.
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The United States Department of Agriculture (USDA) has taken delivery of more than 5000 MBX3 units in the last 12 months through distribution partner 3D Marketing.
Some of CSI's largest marine customers also purchase CSI's combination GPS and beacon receivers and antennas, featuring the ceramic filter, which provide the best location accuracy in a highly integrated product.
"Integrating the ceramic filter into our GPS products gives our products important price and performance advantages over our competition", stated Stephen Verhoeff, President and CEO.
"Integrating the filter in the SBX3A receiver enables us to offer our customers lower prices while also improving our margins".
Typical frequency filters are constructed using metal inductors and must be individually tuned and tested for frequency accuracy.
"These inductor-based filters can fall out of tune over time.
Our ceramic filter is shipped completely tuned - and stays fully tuned", says Verhoeff.
Frequency filters lay between the antenna and the receiver.
They are essential components for any type of radio receiver because they filter out unwanted frequencies so the receiver accepts only the "channels" that are required for the application in question.
CSI's ceramic filter for DGPS rejects all unwanted frequencies and precisely isolates the differential correction signals broadcast from beacon reference stations around the world.
The signals are then cleanly transmitted to CSI's beacon receiver engine.
Ceramic material has a very high quality for precise tuning to a particular frequency with minimal susceptibility to out-of-band interference, a very common problem in low-frequency radio spectrum where differential signals reside.
Ceramic is also very stable over temperature variations.
The most significant advantage of the ceramic filter architecture is the increased out-of-band rejection.
This permits the receiver to digitise the entire beacon band so search-and-tracking algorithms can be implemented in software rather than in hardware.
The sampling of the entire band permits multiple channels to be tracked with software.
The high rejection of the ceramic filter also permits the digitising rates to be lower, which reduces power consumption and processor loading.
As a result, CSI's simplified solution reduces overall manufacturing costs.
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