15,235 research outputs found

    Current Mirror With Programmable Floating Gate

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    Systems and methods are discussed for using a floating-gate MOSFET as a programmable reference circuit. One example of the programmable reference circuit is a programmable voltage reference source, while a second example of a programmable reference circuit is a programmable reference current source. The programmable voltage reference source and/or the reference current source may be incorporated into several types of circuits, such as comparator circuits, current-mirror circuits, and converter circuits. Comparator circuits and current-mirror circuits are often incorporated into circuits such as converter circuits. Converter circuits include analog-to-digital converters and digital-to-analog converters.Georgia Tech Research Corporatio

    Analog-to-digital Converter With Programmable Floating Gate

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    Systems and methods are discussed for using a floating-gate MOSFET as a programmable reference circuit. One example of the programmable reference circuit is a programmable voltage reference source, while a second example of a programmable reference circuit is a programmable reference current source. The programmable voltage reference source and/or the reference current source may be incorporated into several types of circuits, such as comparator circuits, current-mirror circuits, and converter circuits. Comparator circuits and current-mirror circuits are often incorporated into circuits such as converter circuits. Converter circuits include analog-to-digital converters and digital-to-analog converters.Georgia Tech Research Corporatio

    Single-Flux-Quantum Bipolar Digital-to-Analog Converter Comprising Polarity-Switchable Double-Flux-Quantum Amplifier

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    We present a single-flux-quantum (SFQ)-based digital-to-analog converter (DAC) generating bipolar output voltages, in which the key component is a polarity-switchable double-flux-quantum amplifier (PS-DFQA). The DAC comprised a dc/SFQ converter, an 8-bit variable pulse-number-multiplier (PNM), and a 8-fold PS-DFQA integrated on a single chip. SFQ pulse-frequency modulation was employed to realize variable output voltage amplitude, for which the multiplication factor of the variable-PNM was controlled by a commercial data generator situated at room temperature. The variable-PNM realized 8-bit resolution with a multiplication factor between 0 and 255. Bias currents fed to the 8-fold PS-DFQA were polarity-switched in synchronization with the digital code for the variable-PNM. The whole circuits including I/O elements were designed using SFQ cell libraries, and fabricated using a niobium integration process. Sinusoidal bipolar voltage waveform of 0.38 mVpp was demonstrated using a reference signal source of 43.94 MHz

    Baseband analog front-end and digital back-end for reconfigurable multi-standard terminals

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    Multimedia applications are driving wireless network operators to add high-speed data services such as Edge (E-GPRS), WCDMA (UMTS) and WLAN (IEEE 802.11a,b,g) to the existing GSM network. This creates the need for multi-mode cellular handsets that support a wide range of communication standards, each with a different RF frequency, signal bandwidth, modulation scheme etc. This in turn generates several design challenges for the analog and digital building blocks of the physical layer. In addition to the above-mentioned protocols, mobile devices often include Bluetooth, GPS, FM-radio and TV services that can work concurrently with data and voice communication. Multi-mode, multi-band, and multi-standard mobile terminals must satisfy all these different requirements. Sharing and/or switching transceiver building blocks in these handsets is mandatory in order to extend battery life and/or reduce cost. Only adaptive circuits that are able to reconfigure themselves within the handover time can meet the design requirements of a single receiver or transmitter covering all the different standards while ensuring seamless inter-interoperability. This paper presents analog and digital base-band circuits that are able to support GSM (with Edge), WCDMA (UMTS), WLAN and Bluetooth using reconfigurable building blocks. The blocks can trade off power consumption for performance on the fly, depending on the standard to be supported and the required QoS (Quality of Service) leve

    Digital control of diode laser for atmospheric spectroscopy

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    A system is described for remote absorption spectroscopy of trace species using a diode laser tunable over a useful spectral region of 50 to 200 cm(-1) by control of diode laser temperature over range from 15 K to 100 K, and tunable over a smaller region of typically 0.1 to 10 cm(-1) by control of the diode laser current over a range from 0 to 2 amps. Diode laser temperature and current set points are transmitted to the instrument in digital form and stored in memory for retrieval under control of a microprocessor during measurements. The laser diode current is determined by a digital to analog converter through a field effect transistor for a high degree of ambient temperature stability, while the laser diode temperature is determined by set points entered into a digital to analog converter under control of the microprocessor. Temperature of the laser diode is sensed by a sensor diode to provide negative feedback to the temperature control circuit that responds to the temperature control digital to analog converter

    Self-correcting electronically scanned pressure sensor

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    A multiple channel high data rate pressure sensing device is disclosed for use in wind tunnels, spacecraft, airborne, process control, automotive, etc., pressure measurements. Data rates in excess of 100,000 measurements per second are offered with inaccuracies from temperature shifts less than 0.25% (nominal) of full scale over a temperature span of 55 C. The device consists of thirty-two solid state sensors, signal multiplexing electronics to electronically address each sensor, and digital electronic circuitry to automatically correct the inherent thermal shift errors of the pressure sensors and their associated electronics

    Design of a ROIC for scanning type HgCdTe LWIR focal plane arrays

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    Design of a silicon readout integrated circuit (ROIC) for LWIR HgCdTe Focal Plane is presented. ROIC incorporates time delay integration (TDI) functionality over seven elements with a supersampling rate of three, increasing SNR and the spatial resolution. Novelty of this topology is inside TDI stage; integration of charges in TDI stage implemented in current domain by using switched current structures that reduces required area for chip and improves linearity performance. ROIC, in terms of functionality, is capable of bidirectional scan, programmable integration time and 5 gain settings at the input. Programming can be done parallel or serially with digital interface. ROIC can handle up to 3.5V dynamic range with the input stage to be direct injection (DI) type. With the load being 10pF capacitive in parallel with 1MΩ resistance, output settling time is less than 250nsec enabling the clock frequency up to 4MHz. The manufacturing technology is 0.35μm, double poly-Si, four-metal (3 metals and 1 top metal) 5V CMOS process

    Development of an interface for an ultrareliable fault-tolerant control system and an electronic servo-control unit

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    The NASA Ames Research Center sponsors a research program for the investigation of Intelligent Flight Control Actuation systems. The use of artificial intelligence techniques in conjunction with algorithmic techniques for autonomous, decentralized fault management of flight-control actuation systems is explored under this program. The design, development, and operation of the interface for laboratory investigation of this program is documented. The interface, architecturally based on the Intel 8751 microcontroller, is an interrupt-driven system designed to receive a digital message from an ultrareliable fault-tolerant control system (UFTCS). The interface links the UFTCS to an electronic servo-control unit, which controls a set of hydraulic actuators. It was necessary to build a UFTCS emulator (also based on the Intel 8751) to provide signal sources for testing the equipment
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