Serial Data Stream Research Articles

Testing High-Frequency Electronic Signals With Reflection-Mode Electroabsorption Modulators

Remote testing of microwave signals to 25 GHz and digital signals to 12.5 Gb/s is demonstrated through fiber-optic cables. Reflection-mode electroabsorption modulators are used as high-impedance transducers to measure voltage and inject current. Transducers are imbedded in wafer probes, printed circuit probes and microwave packages for various applications including sensing incident and reflected microwave signals, probing serial data streams on printed circuit boards, probing digital and microwave monolithic integrated circuits, and performing time-domain reflectometry. Principal advantages of this technology are that it allows test equipment to be located at large distances from the devices being tested and that broadband signals can be remotely observed with little distortion

All-optical half adder using an SOA and a PPLN waveguide for signal processing in optical networks

We demonstrate an all-optical half adder for bit-wise addition of two serial data streams that simultaneously generates Sum and Carry outputs. The module performs the required XOR and AND operations using only two nonlinear optical elements. Difference Frequency Generation in a periodically poled lithium niobate waveguide serves as the AND gate and cross-gain modulation in a semiconductor optical amplifier is employed to generate the XOR output. Error free operation for RZ data is reported.

Scanning Fluorescence Correlation Spectroscopy: A Tool for Probing Microsecond Dynamics of Surface-Bound Fluorescent Species

In this report, a combined imaging and fluorescence correlation spectroscopy (FCS) method is described and its ability to characterize microsecond fluctuations in the fluorescence emission of a sample is demonstrated. A sample scanning laser confocal microscope is operated in the customary way while recording the time that each photon is detected with a time resolution of 50 ns using a low-cost counting board. The serial data stream of photon detection times allows access to fluorescence signal fluctuations that can be used to characterize dynamics using correlation methods. The same data stream is used to generate images of the sample. Using the technique, we demonstrate that it is possible to characterize the kinetics of transitions to and from nonemitting or "dark" states of the fluorescent dyes DiIC16 and ATTO 520. Results are similar to, but deviate slightly from, a model that has been frequently used for extracting singlet-triplet: conversion rates using conventional solution-based FCS. Like conventional FCS, the concentration, or in our case the areal density of coverage, of fluorescent species can also be obtained. Many single-molecule fluorescence experiments aim to extract kinetics from intensity trajectories; this method may be used as a rapid and convenient technique for characterization of surface-linked or thin-film samples prior to performing the more time and effort intensive single-molecule measurements. Besides the capacity to measure photophysical phenomena, the surface-sensitive FCS method could also be applied for measuring conformational changes or interaction kinetics for species immobilized on a surface. One possible scenario is measurements of the frequency and duration of association of ligand-receptor pairs where a fluorescently labeled component is freely diffusing and the other is surface immobilized. Given that microarrays of custom-designed, surface-immobilized peptides and nucleic acids are now readily available, the ability to sensitively measure association and dissociation rates of the surface-linked species with a freely diffusing species could be a useful extension to what has already become an extremely important tool for characterizing the interactions of biomolecules.

Off-detector electronics for a high-rate CSC detector

Data acquisition (DAQ) electronics are described for a system of high-rate cathode strip chambers (CSC) in the forward region of A Toroidal LHC ApparatuS (ATLAS) muon spectrometer. The system provides serial streams of control signals for switched capacitor array analog memories on the chambers and accepts a total of nearly 294 Gbit/s in serial raw data streams from 64 chambers in the design configuration. Processing of the data is done in two stages, leading to an output bandwidth of 2.56 Gbit/s. The architecture of the system is described, as are some important signal processing algorithms and hardware implementation details. Although designed for a specific application, the architecture is sufficiently general to be used in other contexts.

A 2-Gbaud 0.7-V swing voltage-mode driver and on-chip terminator for high-speed NRZ data transmission

A large-swing, voltage-mode driver and an on-chip termination circuit are presented for high-speed nonreturn-to-zero (NRZ) data transmission through a copper cable. The proposed driver with active pull-up and pull-down can generate a 700-mV signal to deliver a 2 Gbaud serial NRZ data stream. Low output impedance offered by simple negative-feedback resistors alleviates the detrimental effect of the parasitic capacitance by supplying fast current impulses. A proposed on-chip termination circuit provides termination impedance to a mid-supply termination voltage with the benefit of reduced parasitic capacitance and better termination characteristics compared with off-chip termination. The driver and termination circuits have been incorporated in a 2 Gbaud transceiver chip and fabricated in 0.35 /spl mu/m CMOS technology. Measurements show a 1.4 V differential swing with a slew rate of 2.5 V/ns at the receiver output and a 65% reduction of reflection by the on-chip termination circuit with power consumption of 191 mW at 3.3 V supply.

A compact readout system for multi-pixel hybrid photodiodes

The excellent properties of the recently developed multi-pixel hybrid photodiodes (M-HPD) will be easier to exploit following the development of the new hybrid read-out circuits described in this paper. This system will enable all of the required read-out functions to be accommodated on a single board into which the M-HPD is plugged. The design and performance of a versatile system is described in which a trigger-signal, derived from the common-side of the silicon anode in the M-HPD, is used to trigger the readout of the 61-anode pixels in the M-HPD. The multi-channel amplifier section is based on the use of a new, commercial VLSI chip, whilst the read-out sequencer uses a chip of our own design. The common anode signal is processed by a fast amplifier and discriminator to provide a trigger signal when a single event is detected. In the prototype version, the serial analogue output data-stream is processed using a PC-mounted, high speed ADC. Results obtained using the new read-out system in a compact gamma-camera and with a small muon tracking-chamber demonstrate the low-noise performance of the system. The application of this read-out system in other position-sensitive or multi-anode photomultiplier tube applications are also described.

The front-end analog and digital signal processing electronics for the drift chambers of the Stanford Large Detector

The front-end signal processing electronics for the drift chambers of the Stanford Large Detector (SLD) at the Stanford Linear Collider are described. The system is implemented with printed-circuit boards which are shaped for direct mounting on the detector. Typically, a motherboard comprises 64 channels of transimpedance amplification and analog waveform sampling, analog-to-digital conversion, and associated control and readout circuitry. The loaded motherboard thus forms a processor which records low-level waveforms from 64 detector channels and transforms the information into a 64 kB serial data stream. The package performs calibration functions, measures leakage currents on the wires, and generates wire hit patterns for triggering purposes. The construction and operation of the electronic circuits utilizing monolithic, hybridized, and programmable components are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

10-MHz 64-bit error-tolerant signature recognition circuit

A circuit which identifies a 64-bit synchronization word in a serial incoming data stream is discussed. The signature is identified when the incoming data stream matches a previously known and stored signature. It is also possible to program the number of bit errors permissible for recognition of the signature. The circuit was fabricated in a 1.5- mu m CMOS technology for use in a D2MAC television decoder. The circuit operates at data rates up to 20 MHz and covers an area of 1.4*0.1 mm/sup 2/. The possible applications in image recognition and string identification in text are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A 128 K*8 70-MHz multiport video RAM with auto register reload and 8*4 block WRITE feature

An 80-ns 1-Mb multiport video random-access memory (VRAM) can be organized as 128 K*8 or 256 K*4. Uninterrupted serial data streams of 70 MHz are achieved by combining pipelining and interleaving techniques with an internally triggered automatic memory-to-register transfer mechanism. DRAM bandwidth is enhanced by a block WRITE feature which can write as many as four column address locations in every CAS cycle. The write-per-bit feature has been expanded by including an on-chip write-per-bit latch and an extended mode of operation to simplify its use in a wider range of systems. The VRAM is fabricated in a 1 mu m CMOS technology using double-level poly/polycide, single level metal, and trench DRAM storage capacitors for high noise immunity. >

Multiplexing system for organ having plural manuals

An electronic organ, particularly of the institutional type employing classical voicing, having Swell and Great manuals as well as a full pedalboard wherein the manuals and pedalboard are multiplexed simultaneously to produce a plurality of synchronized serial data streams. Intermanual coupling is accomplished by connecting the data stream from one manual to the footage generation circuit of another manual, and tab footages are generated for each manual by utilizing tapped shift registers introducing controlled amounts of delay of the keyboard data before demultiplexing thereof. There is a bank of demultiplexer-keyers for each voice, such as flutes, principals, complex and percussion, which receive the serial data streams from one or more of the footage generators. The demultiplexer-keyers are supplied with tones and function to demultiplex the serial data streams and provide tones selected in accordance with the keydown pulses in the serial data streams to the voicing circuitry. Transposition is accomplished by transposing the demultiplex latch command ahead or behind in time so that the data stream is latched either early or late by one or more time slots depending on the amount of transposition selected. An automatic bass feature permits monophonic bass notes to be played without having to play the pedals, and this is accomplished by coupling into the pedal data stream the lowest data bit originating from the Great manual. Because the footages are generated by selectively delaying the data streams, each manual is scanned twice and the data is gated off on alternate scans to permit the data streams to be supplemented with the lower frequency footage data.

Plural manual organ having transposer

First Page

Mixture generator for electronic organ

An electronic organ, particularly of the institutional type employing classical voicing, having Swell and Great manuals as well as a full pedalboard wherein the manuals and pedalboard are multiplexed simultaneously to produce a plurality of synchronized serial data streams. Intermanual coupling is accomplished by connecting the data stream from one manual to the footage generation circuit of another manual, and footages are generated for each manual by utilizing tapped shift registers introducing controlled amounts of delay of the keyboard data before demultiplexing thereof. There is a bank of demultiplexer-keyers for each voice, such as flutes, principals, complex and percussion, which receive the serial data streams from one or more of the footage generators. The demultiplexer-keyers are supplied with tones and function to demultiplex the serial data streams and provide tones to the voicing circuitry selected in accordance with the keydown pulses in the serial data streams. Transposition is accomplished by transposing the demultiplex latch command ahead or behind in time so that the data stream is latched either early or late by one or more time slots depending on the amount of transposition selected. An automatic bass feature permits monophonic bass notes to be played without having to play the pedals, and this is accomplished by coupling into the pedal data stream the lowest data bit originating from the Great manual. Mixtures are generated by selectively delaying the serial data bits both by octave and sub-octave amounts and then combining the delayed data before demultiplexing thereof. The mixture content, which is either unison-mutation-unison or mutation-unison-mutation, is selected depending on the octave of the keyboard in which the key or keys are depressed.

Stratospheric Aerosol And Gas Experiment II Instrument: A Functional Description

Design and performance data are presented for the Strato-spheric Aerosol and Gas Experiment II (SAGE II) instrument, which has been developed for the Earth Radiation Budget Satellite (ERBS). SAGE II is designed to monitor globally the vertical distribution of stratospheric aerosols, ozone, water vapor, and nitrogen dioxide by measuring the ex-tinction of solar radiation through the earth's atmosphere during the ERBS observatory solar occultations. Solar radiation is reflected from a flat scanning mirror into a Cassegrain telescope, which forms a solar image on the entrance slit of a grating spectrometer. The SAGE II instan-taneous field of view is scanned along the vertical solar diameter by the elevation scan mirror. The entire optical system is contained within an azimuth gimbal that tracks the solar radiometric centroid during the data event. This spectrometer, with help from three interference filters, iso-lates seven spectral wavelengths ranging from 0.385 um to 1.02 um. All seven channels use silicon photodiode detectors operated in the photo-voltaic mode. Detector outputs are multiplexed into a serial data stream for readout by the ERBS telemetry system. Each output is sampled 64 times per second and digitized to 12 bit resolution. SAGE II is a third generation instrument, following the highly successful Stratospheric Aerosol Measurement II (SAM II) and SAGE programs.

Cutting Force Measurement of a Rotating Tool by Means of Optical Data Transmission

The study proposes a new way to accurately measure transient cutting forces of a rotating tool such as a milling cutter from the side of tool. The transmission of cutting forces through a slip ring or a FM telemeter is liable to be affected by noises. Therefore, a device to obtain reliable cutting data has been required to analyze the cutting phenomena, In the measurement system developed, amplified output signals from strain gauge bridges are digitized using an AD converter and then converted to continuous serial data streams to optically transmit them outside a machine tool by use of LED. Received serial data streams by a photo sensor are conversely restored to parallel data, which are immediately processed by a personal computer. The transient cutting forces can be measured without any trouble. As a result, this method was found to be very practical and also applicable to a variety of measuring fields requisite for non-contacting data transmission.

High note priority monophonic brass keyer system

First Page

Method and apparatus for memorizing an accompaniment passage

First Page

Multiplex chime generator

First Page

Bit-slice microprocessors in h.f. digital communications

A 2.4 kbit/s baseband modem is being designed for use at h.f., incorporating modulation/demodulation techniques that are matched to those frequencies and the problems associated with them. Fed by a continuous serial datastream, the modulator functions are implemented wholly by a bit-slice microprocessor, and controlled by another more conventional microprocessor. Analogue output waveforms are generated in a d/a converter, which is driven by the bit-slice machine. Demodulation is performed in a similar device, using an a/d input and giving a serial output.

Automatic arpeggio for multiplex keyboard

First Page

Data detection methods vs head resolution in digital magnetic recording

The detection methods for determining the presence of a magnetically recorded bit depend on the operating conditions of the magnetic recording head and media. The Bit Density curve which best describes the head and media operating conditions is divided into four regions of interest. Methods for data detection suitable for each of the regions are listed together with block diagrams of typical detection circuits. Circuit parameters that effect correct data bit placement in a serial data stream are discussed.