Dynamic range

About: Dynamic range is a research topic. Over the lifetime, 7576 publications have been published within this topic receiving 101739 citations. The topic is also known as: DNR & DR.

Optical carrier filtering for signal/noise and dynamic range improvement

Abstract: A method and apparatus for improving the signal-to-noise ratio (SNR) and dynamic range of an optical fiber system. An optical fiber system (10) includes a laser(12) that produces a coherent light signal conveyed over an optical fiber (14) to a Mach-Zehnder modulator (16). An input signal modulates the coherent light, producing modulated side bands, which together with the carrier comprise a modulated light signal. The modulated light signal is filtered using an integrated optical filter (24) that substantially attenuates the carrier frequency, while passing light at the frequency of the modulated side bands. A detector (28) demodulates the filtered light with a substantially greater SNR than would otherwise have been possible. In one preferred form of the invention, the integrated optical filter comprises an imbalanced interferometer (40), and in another embodiment, tile interferometer produces imperfect nulls aligned with the carrier frequency. A relatively higher power laser(12) can be used without damage to detector (28), since the integrated optical filter substantially reduces the average power of the modulated light by attenuating the carrier, thereby enhancing SNR and dynamic range of the system.

Bandpass sigma delta converter suitable for multiple protocols

Abstract: Improved integration and simplified construction of direct conversion receivers is achieved by providing selectivity in the early stages of a sigma delta converter to reject adjacent channel signals and thereby allow greater dynamic range for the desired input signals. A bandpass sigma delta converter is taught which is suitable for use with signals having multiple protocols. In a first stage, an aliased input signal is applied to two filters having desired and preferably programmable filter characteristics which provide selectivity to the input signal. A third filter is utilized having a programmable center frequency, which receives as an input signal the sum of the filtered input signal plus the quantization noise of the first stage. This provides a first intermediate output signal of desired selectivity. Quantization noise of the first stage is also applied to a second filter stage which provides a second intermediate output signal having a first component related to the quantization noise of the first stage, and a second component which is the shaped quantization noise of the second stage. The first and second intermediate output signals are combined in order to provide a desired output signal in which the original input signal has been filtered to provide a desired selectivity and converted to a digital signal while the quantization noise of the first stage has been cancelled, and the quantization noise of the second stage has been shaped by a desired function and converted to a digital signal independent of the input signal shaping.

A Radiation Tolerant Laser Driver Array for Optical Transmission in the LHC Experiments

Abstract: A 3-way Laser Driver ASIC has been implemented in deep-submicron CMOS technology, according to the CMS Tracker performance and rad-tolerance requirements. While being optimised for analogue operation, the full-custom IC is also compatible with LVDS digital signalling. It will be deployed for analogue and digital transmission in the 50.000 fibre link of the Tracker. A combination of linearization methods allows achieving good analogue performance (8-bit equivalent dynamic range, with 250 MHz bandwidth), while maintaining wide input common-mode range (±350 mV) and power dissipation of 10 mW/channel. The linearly amplified signals are superposed to a DC-current, programmable over a wide range (0-55 mA). The latter capability allows tracking of changes in laser threshold due to ageing or radiation damage. The driver gain and laser bias-current are programmable via a SEU-robust serial interface. The results of ASIC qualification are discussed in the paper.

Switched detector for beam position monitor

Abstract: The NSLS (National Synchrotron Light Source) storage rings use sets of four button electrodes to determine the transverse position of the stored electron beam in the vacuum chamber. By means of GaAs switches, the 211 MHz component of the induced signals on each of the four buttons is measured in turn by a single amplifier-detector channel. These signals are then stored in four sample and hold circuits. The measurement cycle is repeated at a rate of 40 kHz. The required sums and differences of these signals are obtained by analog means. The results are normalized with respect to beam intensity by servoing the gain of the amplifier-detector channel such that the sum of the signals from the four buttons is maintained at a fixed value. The prototype receiver provides +or-20 mu m resolution within a 300 Hz bandwidth over a 30 dB dynamic range. The receiver is relatively insensitive to beam energy and to the number of bunches stored in the machine. >

High-Density Silicon Photomultipliers: Performance and Linearity Evaluation for High Efficiency and Dynamic-Range Applications

Abstract: Silicon photomultipliers (SiPM) are photodetectors that have obtained a growing attention in the last years. They have single photon sensitivity, but also a high dynamic range: the output current signal is proportional to the number of detected photons and it is possible to distinguish up to tens of photon per each light pulse. In Fondazione Bruno Kessler (Trento, Italy) we developed the so called high-density SiPMs, with narrow trenches to isolate the cells (i.e. single-photon avalanche diodes) and with high fill factor. These detectors feature high photon detection efficiency and high dynamic range. Moreover, the reduction of the cell size reduces the correlated noise (i.e. lower crosstalk between cells and lower afterpulsing probability) and it makes the single-cell response faster, increasing the maximum counting rate. These characteristics can be very important in applications like light detection and ranging, spectroscopy, and physics experiments. In this paper, we present the structure of high-density SiPMs and their performance. In particular, the photon detection efficiency, the photon number resolving capabilities, the linearity versus photon flux, and the single-photon time resolution, investigating how these parameters change with the cell pitch.