Richard Hirn

Bio: Richard Hirn is an academic researcher from Alcatel-Lucent. The author has contributed to research in topics: Signal & Zero crossing. The author has an hindex of 2, co-authored 5 publications receiving 21 citations.

Regulation of preconduction current of a laser diode using the third derivative of the output signal

Abstract: A process for controlling the preconduction current of a laser diode that operates in conjunction with a monitor diode in a control circuit with operational amplifiers, comprising signal processing filters, an electric supply unit such as, e.g., a power source, and a zero crossing detector, where the laser diode (5a) is driven by a linear current ramp signal provided by the supply unit, that the output signal (16) of the monitor diode (15) is differentiated three times, and that, when a zero crossing of the triple-differentiated monitor diode output signal (16) is detected, an optimum current of the current ramp signal is retained by the action of the zero passage detector.

The Bookshop Project: An Austrian Interactive Multimedia Application Case Study

Abstract: As field trials all over Europe show, Interactive Multimedia Services (IMMS) are usually considered only for the market of private households with services like ‘Video on Demand’ and ‘Teleshopping’ via TV and Set Top Box in the living room at home.

Optical subscriber interconnect system

Abstract: To match the inherent needs of data traffic, office communications demand medium-speed connectionless packet transport in addition to circuit-switched voice and data transmission. Optical solutions to this requirement should be low in cost rather than extremely high in performance to be cost competitive with copper systems. A subscriber-premises system will be proposed which combines a digital private automatic branch exchange (PABX) with local area network (LAN) functionality. It is based on a double-star passive optical network, extending to optical wall outlets. The subsets with telephone functionality provide the opto/electrical conversion and give access to the packet channel via Terminal Adaptors (TA). Different types of customer LANs may coexist on the same network, since their data frames are embedded in an intermediate MAC-layer. The feasibility of transmission over multimode fibers at not aggregate bit rate of approx. 140 Mb/s at 1300 nm downstream and 780 nm upstream allowing the use of low-cost components (e.g. 780 nm compact-disc laser diodes) has been experimentally investigated. Calculations predict cost-of-ownership parity with conventional copper-based PABXs without LAN functionality and a cost-advantage over the usual separate LAN+PABX installations. The network topology, protocol and the implications of multimode transmission on the system will be discussed.

Bias power supply for laserdiode

Abstract: A method for controlling the bias current of a laser diode which interacts with a monitor diode in a control loop having operational amplifiers, comprising a signal processing filter, an electrical supply unit (such as a power source for example), and a zero-crossing detector, the laser diode (5a) being driven by a linear current ramp signal which is emitted by the supply unit, the output signal (16) from the monitor diode (15) being differentiated three times, and, on detection of a zero crossing of the triple differentiated monitor-diode output signal (16), an optimum current intensity for the current ramp signal generator being fixed by the zero-crossing detector.

Vorstromregelung für Laserdiode

Abstract: Verfahren zur Regelung des Vorstromes einer mit einer Monitordiode in einem Regelkreis mit Operationsverstarkern zusammenwirkenden Laserdiode, umfassend Signalverarbeitungsfilter, eine elektrische Versorgungseinheit, wie z.B. eine Stromquelle, und einen Nulldurchgangsdetektor, wobei die Laserdiode (5a) von einem von der Versorgungseinheit abgegebenen linearen Stromrampensignal betrieben wird, das das Ausgangssignal (16) der Monitordiode (15) dreifach differenziert wird, und das bei Erkennen eines Nulldurchganges des dreifach differenzierten Monitordioden-Ausgangssignals (16) durch den Nulldurchgangsdetektor eine Optimalstromstarke des Stromrampensignalgenerators festgehalten wird.

Pixel circuit display apparatus and electronic apparatus equipped with current driving type light-emitting device

Abstract: A display apparatus is provided with a current driving type light-emitting device and a driving device for controlling a driving current flowing through the light-emitting device for each pixel of the display apparatus. The display apparatus consists of power source units for supplying power for causing a driving current to flow via the driving device to the light-emitting device via a power source wire, and signal wire driving units for supplying a data signal to the driving device via signal wires. In addition, voltage adjusting units adjust a voltage for the power source units or a data signal from the signal wire driving units so that a quantity of a driving current flowing through the light-emitting device when a data signal of a predetermined voltage is supplied to the driving device via signal wires or a quantity of emitted light emitted from the light-emitting device comes close to a predetermined reference value.

Pixel circuit, display device and electronic equipment having current-driven light-emitting device

Abstract: A display device (100) includes, for every pixel, a current-driven light-emitting device (224), and a driving element (223) for controlling a driving current flowing through the light-emitting device in accordance with the voltage of a data signal. The display device further includes power-supply sections (13, 14) for supplying, via a power-supply wiring, power for causing the driving current to flow through the light-emitting device via the driving element, and signal wiring driving sections (11, 12) for supplying the data signal to the driving element via signal wirings (131, 132). Voltage regulating sections (16 to 23) regulate the power from the power-supply sections or the voltage of the data signal from the signal wiring driving sections, so that the quantity of the driving current flowing through the light-emitting device or the quantity of light emitted from the light-emitting device when a data signal of a predetermined voltage is supplied to the driving element via the signal wirings approaches to a predetermined reference value.

Penlight and touch screen data input system and method for flat panel displays

Abstract: System, device, and method for receiving or sensing touch or light input to an emissive display such as to a OLED display using the same or different sensors as are used to sense and maintain a pixel luminance. Penlight and touch screen data input system and method for display. A sidelight illuminated display and touch panel input device. Method and device for reading display pixel emission and ambient luminance levels. Emissive display having sensing for luminance stabilization and user light or touch screen input. Method and device for emissive display using shielded or partially shielded sensors. Emissive pixel display device characterized in that photon sensors are disposed within pixels and operated to sense photons emitted by emitter within pixel and ambient photons emitted by sources outside pixel, sensed internally emitted photons being for luminance feedback control and sensed ambient photons being used to detect external light source or sources.

How modal noise in multimode fibers depends on source spectrum and fiber dispersion

Abstract: The speckle contrast for multimode fibers, and thus the modal noise, is essentially given by the impulse response of the fiber and the power spectrum of the source. Theoretical and experimental results show that laser sources with a large spectrum of narrow longitudinal modes may cause high speckle contrast and important modal noise over more than 1-km length in graded-index multimode fibers.

Method and apparatus for controlling pixel emission

Abstract: Emission from a pixel is received by a sensor. The sensor is coupled to a control unit that receives or determines a value of the sensor's measurable parameter during operation of the pixel. A target value is coupled to the control unit, allowing the control unit to compare the measurable sensor parameter and the target value. The control unit is coupled to a pixel driver operable to alter the emission from the pixel. The pixel driver may vary the emission from the pixel until the measurable sensor parameter indicates that the target value has been achieved. The target value may be determined based on a calibration of the sensor. A plurality of target values may be stored in a look-up table. Passive and active matrix displays may be controlled in accordance with methods and apparatuses of the invention.