N251-048 TITLE: Analog to Digital Converter for Low Noise Electromagnetic Measurements

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Microelectronics

OBJECTIVE: Design a specialized Analog to Digital Converter (ADC) to support the data acquisition needs of extremely low-noise underwater electromagnetic (UEM) sensors, enabling measurements of lower UEM signals.

DESCRIPTION: The Navy seeks a specialized ADC technology that interfaces with low-noise Underwater Electromagnetic (UEM) sensors to achieve extremely low system noise levels. The ADC shall support specific magnetometers and electropotential sensors that are currently used by U.S. Navy measurement facilities.

UEM sensor technologies (i.e., magnetometers and underwater electropotential sensors) continue to improve at a rate that is faster than the available commercial off-the-shelf (COTS) ADC solutions. This disparity in technology growth has resulted in UEM sensors no longer driving the noise floor of the acquisition system. The COTS ADC solutions were generated from a demand in significantly different sensors and mediums. With some of the modern sensors on the market, ADCs are the limiting factor for improving total system noise levels. There is evidence from the research communities and industry, that shows ADC performance can be optimized for specific applications.

Research into the specific composition of ADC circuits is needed to acquire either magnetic field or electropotential data. This needs to be done to ensure the most optimal performance. Additionally, the form factor of existing COTS ADCs can drive the minimum size requirements of UEM measurement systems. A smaller form factor would allow for more flexibility in arrangements, locations, and quantity considerations of field-able systems.

The ADC will be evaluated against other commercially available ADCs supporting identical sensors, including the ADCs that have historically been leveraged by U.S. Navy UEM measurement systems. These criteria may include the following, but may not be limited to:

- Dynamic Range

- Resolution

- Sampling Rate (Specifically 6-10 kHz desired)

- Power Consumption

- Effective Signal to Noise Ratio (SNR)

A successful candidate will show the ability to design an ADC that is tailored to a specific measurement device while optimizing ADC performance for common ADC parameters like the ones mentioned above.

PHASE I: Design and develop a concept ADC to meet the requirements in the Description section. The Phase I Option, if exercised, will include the initial ADC design that would be leveraged to build out a prototype for testing in Phase II. Additionally, performance simulations demonstrating the expected noise levels will also be required to move forward with a Phase II award. The circuit design will need to demonstrate simulated noise levels meeting or exceeding advertised noise levels for existing COTS ADC solutions.

PHASE II: Fabricate and deliver a prototype ADC to be lab tested to demonstrate component noise performance to be compared with the simulated results from Phase I. Additionally, the prototype ADC will also be integrated with a UEM sensor in a lab setting to demonstrate system noise performance.

After lab testing is completed and noise levels are demonstrated, if satisfactory with U.S. Navy expectations, the next portion of Phase II will be integrating the ADC prototype into a U.S. Navy measurement system that will be deployed at the South Florida Ocean Measurement Facility (SFOMF) in Dania Beach, FL to demonstrate the total system noise levels in an operational environment to achieve TRL 7.

PHASE III DUAL USE APPLICATIONS: Integrate the Phase II developed ADC prototype into a standard form factor capable of back-fit to existing hardware or forward-fit current and future data acquisition system designs and architectures. Designs would likely support SFOMF systems and other facilities with deployed UEM sensors.

The ADC developed under this project could be utilized for the same type of sensors that are frequently employed for the oil and gas industry. UEM sensors are commonly utilized for oil and gas exploration and lower noise sensors would be more capable for this purpose.

The product will be initially validated in a similar method the prototype was evaluated in Phase II with lab and SFOMF testing with a deployed system. Component certification would be completed by NSWC Carderock, NAVSEA’s engineering agent for underwater electromagnetic measurement systems.

REFERENCES:

1. Beev, Nikolai. "Analog-to-digital Conversion Beyond 20 Bits." CERN Database, 2018, pp. 1-6. https://cds.cern.ch/record/2646282/

2. Bashir, Saima. "Analog-to-digital converters: A comparative study and performance analysis." 2016 IEEE International Conference, Houston, TX, USA, 14-17 May 2018, pp.1-6. https://ieeexplore.ieee.org/document/7813861

KEYWORDS: Analog to Digital Converters (ADC); Acquisition Systems; Underwater Electromagnetic Signatures; Magnetometers; Electropotential; electric field; magnetic field.

TPOC 1: Christopher Tilley
(954) 926-4020
Email: [email protected]

TPOC 2: Frederick Merkel
(301) 227-203
Email: [email protected]

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