The feedback dynamics of brain-computer interfaces in a distributed processing environment

This paper describes a distributed paradigm for human brain-computer interfaces that can incorporate machine learning-directly stimulus feedback to the subject. Specifically, we use OpenBCI hardware and software to capture real-time EEG (Electroencephalography) waveforms from a subject on a host ''client" computer and stream them to another ''server" computer which could perform complex analyses on the waveforms prior to sending commands back to the OpenBCI interface directing alterations to the stimulus. In addition to describing the conceptual system framework, we present here the test results quantifying the closed-loop system latencies under various conditions. Quantifying latency in any feedback control loop (in this case, one that actually contains the human subject's brain) is vital since excess latency can destabilize a system

Software Defined Radio for Carrier and Symbol Timing Extraction

Using LabVIEW, a software-defined radio receiver was developed to extract the phase of the carrier and the symbol timing interval for possible satellite diagnostics. The receiver consists of two main parts: a phase-locked loop and a symbol timing algorithm. Using a Weaver demodulator and a complex-to-complex mixer, the phase of the carrier is extracted from the input signal. A windows-based timing algorithm, compatible with non-return-to-zero and biphase coding, extracts the symbol arrival time interval. Lastly, a two-stage logging algorithm temporarily stores output data in a DRAM buffer before streaming the data to the hard drive for final storage.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit https://telemetry.org/contact-us/ if you have questions about items in this collection

LabVIEW for Software Defined Radio Development

In this project, LabVIEW and LabVIEW FPGA are studied as a possible development environment for software-defined radios. LabVIEW is National Instruments’ proprietary graphical programming language, which uses the dataflow programming paradigm, while LabVIEW FPGA is an addon that enables FPGA programming through LabVIEW. Using National Instruments PXIe-5646R Vector Signal Transceiver and PXIe-7976R FlexRIO FPGA module, the intricacies of developing a software-defined radio are explored. In addition, Xilinx intellectual property blocks available in LabVIEW FPGA are explored and used to develop a software-defined radio receiver.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit https://telemetry.org/contact-us/ if you have questions about items in this collection

THE EFFECTS OF LOSSY EEG COMPRESSION ON ERP ANALYSIS

This paper analyzes lossy data compression in the specific context of event-related potential (ERP) analysis of electroencephalography (EEG) data. The lossy data compression techniques analyzed here are bit-rate quantization and frequency truncation using the discrete cosine transform (DCT). Within the context of both methods it is demonstrated that ERP analysis waveforms yield significant data compression advantages over raw EEG data. It is found from the experimental results that for any given quantization error bound, utilization of ERP analysis requires approximately 3 fewer bits per EEG sample than normalized EEG data. Additionally, given any error bound for frequency truncation, at least 30% more total DCT coefficients can be discarded when utilizing ERP analysis instead of raw EEG data. The results hold significant implications for large-scale medical applications that rely on ERP analysis of EEG data.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Determination of Position Around Near-Earth Asteroids Using Communication Relays

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CAIn this paper we consider the possibility of using a communications system that is operating between probes on the surface of an asteroid and an orbiting satellite to more accurately determine spatial positions. This is done by measuring the round trip communication delay between the orbiter and various surface probes to estimate distance. From these distance measurements, the position can be determined using trilateration - the same basic technique behind the earth-based GPS system. Within the framework of this scenario, the location of the probes or the orbiter can be determined depending on the scenario.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Analysis of Communication Rates in the Proximity of Near-Earth Asteroids

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NVIn this paper we analyze fundamental local-area communication issues related to proximity operations around near-earth asteroids. We are motivated by NASA's plan to send robotic spacecraft to numerous such asteroids in the coming years in preparation for an eventual manned mission. We consider here the case where multiple probes are deposited on the surface of an asteroid and must communicate the data they collect to each other and to earth by using the orbiting `mothership' as a relay. With respect to this scenario, we statistically analyze the ability of surface probes in various locations to communicate with the mothership as well as their abilities to network with one another. For the purposes of this analysis, we assume the simplest possible communications scenario: a surface probe can communicate with the mothership only when it has an unobstructed line of sight. At the frequencies of interest here, line of sight is a necessary condition but it is obviously not sufficient - the end-to-end link margins of our communications system must be high enough to support the desired/required data rates. The work presented in this paper extends our previous research in which we only analyzed the visibility of the locations on the surface of the asteroid. Here, we consider how visibility affects the required communications bandwidth and buffer sizes for both surface-to-spacecraft and surface-to-surface scenarios.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Analysis of Communication Interconnectedness in the Proximity of Near-Earth Asteroids

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, CaliforniaIn this paper we analyze fundamental local-area communication issues related to proximity operations around near-earth asteroids. We are motivated by NASA's plan to send robotic spacecraft to numerous such asteroids in the coming years in preparation for an eventual manned mission. We consider here the case where multiple probes are deposited on the surface of an asteroid and must communicate the data they collect to each other and to earth by using the orbiting `mothership' as a relay. With respect to this scenario, we statistically analyze the ability of surface probes in various locations to communicate with the mothership as well as their abilities to network with one another. For the purposes of this analysis, we assume the simplest possible communications scenario: a surface probe can communicate with the mothership only when it has an unobstructed line of sight. At the frequencies of interest here, line of sight is a necessary condition but it is obviously not sufficient - the end-to-end link margins of our communications system must be high enough to support the desired/required data rates. Nonetheless, this simplistic analysis represents the first step in characterizing the communication system requirement for the asteroid-local portion of the system.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection