Very Low Frequency Receiver front end with high sensitivity and frequency selectivity

ABSTRACT: Diversified Technologies, Inc. (DTI) will design a high performance, low noise analog portion of the VLF receiver front end, optimized for 15 to 60 kHz operation. DTI will integrate the analog front end with a commercial 24 bit oversampled analog-to-digital converter with an output data rate over 200 kHz. Converters of this type combined with a properly designed analog preamplifier will reject unwanted signals by at least 30 dB more than the Stanford AWESOME receiver"s 16 bit converter could tolerate. Finally, DTI recognizes that VLF receivers must be capable of reliable performance in harsh airborne conditions, tolerating far more interference and receive far weaker signals than legacy receivers were designed for. DTI will locate the front end of the receiver within the antenna housing such that the digital signal output is carried via optical fiber to the remote demodulator. The entire antenna and front end may then be electrostatically shielded. BENEFIT: Combining the state-of-the-art in VLF receivers with COTS components will allow for a highly effective, inexpensive solution for the incorporation of AF and Navy VLF transmission systems. Development and fielding of VLF receivers through this SBIR effort builds on DTI"s capabilities in manufacturing MIL-QUAL electronics, and will expand our technical capabilities in two related directions RF systems for the US Military, and VLF subsystems. Both of these areas will broaden current military capabilities in radar and power conversion systems.