ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Meeting the filtering requirements for telemetry transmitters and receivers can be challenging.
Telemetry systems use filters to eliminate unwanted spurious or mixing products. The use of
tunable microwave filters for both L and S Band can improve filter selectivity and provide low
insertion losses in the filter passband. Along with meeting specifications, these microwave
filters with the ability to tune an octave, reduce size and cost by the reduction of multiple, fixed-frequency
filters. As size, weight and power are often a concern with aeronautical telemetry
systems, this paper will demonstrate that microstrip tunable filters can be small in size and use
minimal power.
Telemetry transmitters are subject to difficult spurious emission and interference specifications
and require selective filters to eliminate spurious signals before the final amplification.
Telemetry receivers on the other hand are subject to intense Image and Local Oscillator (LO)
rejection requirements and demand low insertion loss for front-end filtering. Low insertion loss
filtering before the Low Noise Amplifier (LNA) circuit limits degradation to the system noise
figure (NF). By using different filter topologies and state-of-the-art, high-Q varactor diodes,
tunable microwave filters can be optimized for two different functions. The two functions
emphasize either low insertion loss or selectivity. An important design consideration with
tunable filters, when compared to typical fixed frequency filters, is the degraded intermodulation
performance. This is largely due to the non-linear behavior of the varactor diodes.
This paper describes the benefits and limitations of microwave tunable filter architectures
suitable for both aeronautical telemetry transmitters and telemetry receivers. Information on the
computer modeling of varactor diodes will be covered as a critical part of the design. Potential
design considerations for microwave tunable filters will also be covered. Through the use of
simulation software and filter prototypes, this paper presents dramatically improved filter
performance applicable to telemetry transmitters and receivers.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/604532 |
| Date | 10 1900 |
| Creators | Wurth, Timothy J., Rodzinak, Jason |
| Contributors | NuWaves Engineering |
| Publisher | International Foundation for Telemetering |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Proceedings |
| Rights | Copyright © held by the author; distribution rights International Foundation for Telemetering |
| Relation | http://www.telemetry.org/ |
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