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Results for “TIME DIVISION MULTIPLEX”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Queueing analysis of synchronous time division multiplexing with individual source buffering

Synchronous time division multiplexing is analyzed. Packets of information arrive at the system as a compound Poisson process, and are transmitted only during individual periodic intervals. Packet arrivals are blocked (lost) if the system has a finite capacity and is congested. Using the theory of semiregenerative processes, the distribution of the number of packets in the system (system size) is found. This nonstationary distribution is used to determine the complete system behavior, including the delay distributions, the blocking probability, and the density of the system size at arrival instants. Numerical examples illustrate applications of the results given.

Clare, L.↗
NASA NTRS2021

Mitigation of Finite Bandwidth Effects in Time-Division-Multiplexed SQUID Readout of TES Arrays

Time division multiplexing (TDM) is being developed as the readout technology of the X-ray integral field unit (X-IFU), a 3,168-pixel X-ray transition-edge sensor (TES) imaging spectrometer that is part of the European Space Agency's Athena satellite mission. Recent improvements in the low X-ray event count rate performance of TDM have been driven by increases in multiplexer bandwidth and the mitigation of settling transients. These methods and design changes have improved the 32-row multiplexed resolution of a NASA LPA 2.5a array from an initial (2.73 ± 0.03) eV to (1.97 ± 0.01) eV resolution at 5.9 keV. We discuss these recent advances in TDM readout, which have been implemented in an 8-column × 32-row spectrometer that will be deployed at the Lawrence Livermore National Laboratory electron beam ion trap (EBIT) facility, and present a model that will inform the design of future systems.

Transition-edge sensors↗
DOE OSTI2024

Results and Limits of Time-Division Multiplexing for the BICEP Array High-Frequency Receivers

Time-division multiplexing is the readout architecture of choice for many ground and space experiments, as it is a very mature technology with proven outstanding low-frequency noise stability, which represents a central challenge in multiplexing. Once fully populated, each of the two BICEP Array high-frequency receivers, observing at 150 GHz and 220/270 GHz, will have 7776 TES detectors tiled on the focal plane. The constraints set by these two receivers required a redesign of the warm readout electronics. The new version of the standard multichannel electronics, developed and built at the University of British Columbia, is presented here for the first time. BICEP Array operates time-division multiplexing readout technology to the limits of its capabilities in terms of multiplexing rate, noise and cross talk, and applies them in rigorously demanding scientific application requiring extreme noise performance and systematic error control. Finally, future experiments like CMB-S4 plan to use TES bolometers with time-division/SQUID-based readout for an even larger number of detectors.

47 OTHER INSTRUMENTATION↗
DOE OSTI2019

Two-Level Switches for Advanced Time-Division Multiplexing

Superconducting quantum interference device (SQUID)-based time-division multiplexing (TDM) is a mature and widely implemented technology used to read out transition-edge sensor arrays. As the number of pixels in modern arrays continues to increase, a higher multiplexing factor is required to reduce the number of wires and amplifier channels. Yet, as the multiplexing factor is increased, the number of row-select wires (used to turn on a row of TDM SQUIDs in a two-dimensional configuration) also increases, limiting the reduction in array wires. We introduce a more advanced TDM architecture that enforces multi-level switching between subgroups of pixels. We show that this technique can dramatically reduce the number of required row-select lines. We also present the design, fabrication, and testing of a TDM multiplexer incorporating a two-level switch, which implements a second switch for each group of ten TDM pixels. In this application, a multiplexing factor of 100 can be addressed using ten group-select wiring pairs and ten row-select wiring pairs. We demonstrate multiplexer functionality and present measured operating margins of this new TDM multiplexer.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1971

A time-division multiplexing system for asynchronous high-rate telemetry.

A time-division multiplexing system has been developed that is significantly different from commercially available equipments. Multiplexing is achieved by interleaving blocks of data from each source, preceded by a short coded bit pattern specifying the source of that particular block of data. Data blocks are transmitted as they become available from each particular source. Hence, synchronism of the input and output rates is not required. The prototype system can accommodate input rates as high as 461 kbit/sec on a single input channel, and output rates as high as 953 kbit/sec. The system makes possible use of an excess of 90% of channel capacity for information transmittal.

Appel, R. L.↗
DOE OSTI2019

Conflux – An Asynchronous 2-to-1 Multiplexor for Time-Division Multiplexing and Clock-less, Token-less Readout

This paper describes an independent, self-arbitrating asynchronous two-to-one multiplexor called Conflux. Conflux can be used to implement clock-less and token-less Time-Division Multiplexing between two sources. This capability can then be used to create a clock-less and token-less aggregate data bus which can be used as a complete asynchronous readout architecture for a chip, a part of a chip or an entire multi-chip system. Conflux utilizes a classic, four-phased asynchronous handshake on both of its input ports as well as on its output port. Asynchronous Request is bundled with Data to ensure consistent propagation delay. The Request is also differential to account for propagation delay differences between Logical Ones and Zeros. Arbitration between the two Conflux input streams is accomplished by three Set-Reset latches. Finally, Conflux cells were used successfully to implement the readout architecture of the FCP130 prototype chip. Tests indicate single Conflux stage delays of 1.8ns and a bandwidth of approximately 20 Gbps in 130nm CMOS.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Adaptive Time-Division Multiplexing Driving System for Solid State Lighting with Multiple Tunable Channels

Next generation solid state lighting enables unlimited control of light and serve much broader functions beyond the basic lighting for illuminance. The emerging lighting for productivity, well-being, healthcare, and growth have revolutionized the scope of lighting. To empower this unlimited controllability, a multi-channel tunable power-electronics driver is essential but has not been satisfactorily addressed so far. Existing solutions are lossy, large, and expensive, due to introduction of additional buck power conversion stages. This paper proposes a time-division multiplexing (TDM) LED driving system which eliminates those buck stages. The proposed design can directly pair with off-the-shelf pulse width modulated (PWM) controllers and since it inherits entire feature sets, it can achieve low loss at standby and at dimmed condition. The simple analog implementation avoids usage of expensive DSPs/MCU. GaN’s high switching frequency capability can push up the multiplexing frequency so a GaN-based flyback was built and proved the concept.

Xue, Lincoln↗
NASA NTRS1977

Time-division multiplexer uses digital gates

Device eliminates errors caused by analog gates in multiplexing a large number of channels at high frequency. System was designed for use in aerospace work to multiplex signals for monitoring such variables as fuel consumption, pressure, temperature, strain, and stress. Circuit may be useful in monitoring variables in process control and medicine as well.

Myers, C. E.↗
NASA NTRS2018

Methods and Apparatus for Aggregation of Multiple Pulse Code Modulation Channels into a Signal Time Division Multiplexing Stream

Methods and apparatus are provided for telemetry processing using a telemetry processor. The telemetry processor can include a plurality of communications interfaces, a computer processor, and data storage. The telemetry processor can buffer sensor data by: receiving a frame of sensor data using a first communications interface and clock data using a second communications interface, receiving an end of frame signal using a third communications interface, and storing the received frame of sensor data in the data storage. After buffering the sensor data, the telemetry processor can generate an encapsulated data packet including a single encapsulated data packet header, the buffered sensor data, and identifiers identifying telemetry devices that provided the sensor data. A format of the encapsulated data packet can comply with a Consultative Committee for Space Data Systems (CCSDS) standard. The telemetry processor can send the encapsulated data packet using a fourth and a fifth communications interfaces.

Chang, Chen J.↗