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Development of Non-Decade Inductive Voltage Divider Automatic Test Equipment

Description:

TECHNOLOGY AREA(S): Electronics 

OBJECTIVE: Develop fully automated test equipment with an instrument controller and software that accurately divides AC voltage to lower outputs with minimal signal noise using an inductive voltage technique that does not contain a decade resistor design. 

DESCRIPTION: Inductive voltage divider (IVD) test equipment supports multiple military signal operations for communications and electronic intelligence gathering. Additionally, military support teams and centers with test measurement and diagnostic equipment (TMDE) within the transfer, reference, and primary level utilize IVD test equipment. Current decade resistive style IVD test equipment inventory, with an accuracy of +/- 0.5 uV/V, is obsolete and no longer supportable. This aged decade resistive style IVD technology cannot be adapted to run with current Army automated test, measurement, and diagnostic equipment calibration processes. Replacement inventory development delay increases risk of declining readiness and mission availability, as current calibration capability declines due to system failures without available replacement or repair parts available. Commercial-off-the-shelf solutions (COTS) are manually operated and do not support an automated test equipment solution at the accuracy required. Automated IVD devices do not exist. Therefore, no reference COTS products can be directly compared. The IVD automated test equipment (ATE) shall be capable of both manual and remote operation by commands sent from an instrument controller compatible with the latest Army-approved computer operating systems, control software, and drivers over an IEEE-488 bus. Inputs and outputs shall be computer controlled via software that generates all of the measurement, outputs, and input settings to minimize operator interaction. The IVD ATE shall capture and store measurement results in a format compatible with spreadsheet software in a comma or tab-delimited file format. The IVD ATE shall output known variable ratio AC voltage levels; an IVD ATE whose capability includes only fixed ratios as in a decade resistive IVD, is not acceptable. The nominal resolution of the tunable divider network shall be increments of 0.01 up to 100,000:1. The IVD equipment shall be capable of providing tunable inductive voltage division for an input voltage range of 100mVac to 350Vac over the frequency range of 10 Hz to 20 kHz. In addition to known variable ratios, the IVD ATE shall provide preset ratios of 0.1:1, 1:1, 10:1, 100:1, 1000:1, 10,000:1, 100,000:1 with resolution of ±0.01 ppm for each ratio. These ratios are considered to be cardinal points of the IVD ATE's design, and shall be part of the provided capability. An automated IVD using non-switch or contact inductive method will introduce currently unknown signal noise; however, the known signal source quantity will remain the same. The nominal signal-to-noise ratio (SNR) across the voltage and frequency range shall be 1000:1 (40 dB). The SNR shall be 10,000:1 (80 dB) when measured at 1V and 1 kHz. The signal distortion of the IVD ATE shall be quantified through testing of the prototype over its operating range. All certificates and reports for calibration of the IVD ATE shall meet the requirements of ISO/IEC 17025 for traceability to the National Institute of Standards and Technology (NIST).  

PHASE I: Develop, evaluate, and validate innovative materials and techniques as a preliminary design for a selected approach. The Phase I deliverable shall include a report describing the design approaches considered and the feasibility of each approach in fulfilling a completed final product. Hardware and software requirements shall be defined for the proposed method. Modeling and simulation data for the proposed method’s design concept(s) shall be included. Analysis and overall evaluation of the proposed method shall be included in the report. 

PHASE II: The Phase I design shall be utilized to create a functional prototype. Phase II deliverables shall include the delivery of a prototype system and a final report. The prototype system shall demonstrate all of the requirements in Phase I have been met. The final report shall include the prototype design, implemented approaches, test procedures, and results. Prototype design shall include all hardware and software necessary to meet the aforementioned characteristics within the overall IVD test equipment. Any design changes after Phase I need to be documented in the final report with an explanation of why changes were deemed necessary. 

PHASE III: The prototype system shall be matured and finalized. A technology transition plan shall be developed for consideration by pertinent program managers. Commercialization applications include other DoD agencies operating unsupportable IVD test equipment. Additionally, labs and private industry throughout the world market will have applications for automated IVD test equipment with this level of high precision. 

REFERENCES: 

1: Avramov-Zamurovic, S., Waltrip, B., Koffman, A., & Piper, G. (n.d.). A Lecture on Accurate Inductive Voltage Dividers. Lecture. Retrieved from http://www.dtic.mil/docs/citations/ADA574991

2:  Avramov, S., Oldham, N., Jarrett, D., & Waltrip, B. (1993). Automatic inductive voltage divider bridge for operation from 10 Hz to 100 kHz. IEEE Transactions on Instrumentation and Measurement, 42(2), 131-135. doi:10.1109/19.278535

3:  Avramov-Zamurovic, S., Stenbakken, G., Koffman, A., Oldham, N., & Gammon, R. (1995). Binary versus decade inductive voltage divider comparison and error decomposition. IEEE Transactions on Instrumentation and Measurement, 44(4), 904-908. doi:10.1109/19.392879

4:  Homan, D. N., & Zapf, T. L. (1970). Two Stage, Guarded Inductive Voltage Divider for Use at 100 kHz. ISA Transactions, 9. Retrieved from https://www.nist.gov/sites/default/files/documents/calibrations/isa-9-3.pdf.

KEYWORDS: Inductive, Voltage, Divider, Microelectronics, Alternating Current, Test Equipment, Signal Noise 

CONTACT(S): 

Louis Fairman 

(586) 282-8136 

louis.b.fairman.civ@mail.mil 

Scott Faust 

(586) 282-4608 

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