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Miniaturized, Power Efficient C-band Telemetry

Description:

OBJECTIVE: Develop a miniaturized, power efficient C-band telemetry (TM) transmitter with performance comparable to current state of the art miniaturized S-band transmitters. DESCRIPTION: A miniaturized TM subsystem for an airborne transmitter is needed in the 1-2 cubic inch form factor to support existing efforts to miniaturize flight test instrumentation. C-band transmitter RF devices are steadily improving, but their gain and efficiency are several years behind L-band and S-band devices that are available commercially. The challenge of designing test instrumentation with C-Band capable RF devices encompasses a trade space that includes size, power, and link margin requirements. Power consumption is a critical factor, and adequate reserves must be available to the actual equipment being tested. The most difficult challenge is recovering the lost link margin. Moving from 2.2 GHz to 4.4 GHz costs 6 dB in path loss. In theory, the gain of the receiving antenna should increase by 6 dB to compensate for this loss, but in practice, the antenna gain will not improve that much. Any misalignment of the feed or slight shift in dish parabola accuracy will keep the antenna gain from getting the full 6 dB, and telemetry experts estimate that the gain is closer to 3 dB. This leaves the instrument platforms to manage a link margin 3 dB less capable than current operations in S-Band during times when the platforms need more data transmitted to the ground. This may require the transmitter to increase power output from current specification to a 10-watts specification, which will add a new level of complexity to the internal system design and impact to systems power sources. Power consumption and management are thus a critical considerations in unit development. Miniaturized C-Band Transmitter Specific Needs: Size: less than 2 cubic inches Modulation Schemes: All ARTM waveforms (PCM/FM, SOQPSK, CPM) Input Power: Less than 40 Watts RF Output Power: At least 10 Watts Operating Frequency: Selectable between 4400-4940, 5091-5150, and 5925-6700 MHz PHASE I: Design C-band transmitter and develop concepts for telemetry support infrastructure in compliance with Mil-Std-461 EMI/EMC guidelines. Designed unit must be able to operate reliably and safely in concert with other test range electronic devices, including munitions. Designed unit must be able to maintain C-band link margins comparable to those of other TM subsystems operating in S-band. PHASE II: Build a prototype TM transmitter unit and demonstrate that meets the stated performance objectives. Demonstrate capabilities in a test range environment and show that it can operate reliably and safely in concert with other test range electronic devices, including munitions. Demonstrate the ability to maintain C-band link margins comparable to those of other TM subsystems operating in S-band. PHASE III: Integrate new C-band telemetry capabilities into test range environments and show that the unit reliably operates meeting stated objectives. To be successful, the device must comply with IRIG Std RCC106-09, Mil-Std-461 and environmental specification. REFERENCES: 1. Federal Communications Commission (2011). National Broadband Plan accessed at http://www.broadband.gov/download-plan/ on 10 Nov 2011. 2. G. F. Guimares et al.,"S-Band Amplification and S- to C/L-Band Wavelength Conversion Using a TDFA/FOPA Hybrid Amplifier", Annals of Optics (2006). 3. J.F.L. Freitas et al.,"Raman Enhanced Parametric Amplifier Based SC Band Wavelength Converter: Experiment and Simulations", Optics Communications 255, 314318 (2005). 4. Peebles, Peyton Z. Jr, (1998), Radar Principles, John Wiley and Sons, Inc., p 20. 5."Experiment and Simulations", Optics Communications 255, 314318 (2005).
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