We review some usual laser range finding techniques for in- dustrial applications. After outlining the basic principles of triangulation and time of flight (pulsed, phase-shift and frequency modulated continu- ous wave (FMCW)), we discuss their respective fundamental limitations. Selected examples of traditional and new applications are also briefly presented. © 2001 Society of Photo-Optical Instrumentation Engineers.

Laser ranging: a critical review of usual techniques for distance measurement

An experimental technique is described for observing the effects of switching transients in digital MOS circuits that perturb analog circuits integrated on the same die by means of coupling through the substrate Various approaches to reducing substrate crosstalk (the use of physical separation of analog and digital circuits, guard rings, and a low-inductance substrate bias) are evaluated experimentally for a CMOS technology with a substrate comprising an epitaxial layer grown on a heavily doped bulk wafer Observations indicate that reducing the inductance in the substrate bias is the most effective Device simulations are used to show how crosstalk propagates via the heavily doped bulk and to predict the nature of substrate crosstalk in CMOS technologies integrated in uniform, lightly doped bulk substrates, showing that in such cases the substrate noise is highly dependent on layout geometry A method of including substrate effects in SPICE simulations for circuits fabricated on epitaxial, heavily doped substrates is developed >

Experimental Results and Modeling Techniques for Substrate Noise in Mixed-Signal Integrated Circuits

A method and system is provided for programming the digital filter compensation coefficients of a digitally controlled switched mode power supply within a distributed power system. The distributed power system comprises a plurality of point-of-load (POL) regulators each comprising at least one power switch adapted to convey power to a load and a digital controller adapted to control operation of the power switch responsive to a feedback measurement. The digital controller further comprises a digital filter having a transfer function defined by plural filter coefficients. A serial data bus operatively connects each of the plurality of POL regulators. A system controller is connected to the serial data bus and is adapted to communicate digital data to the plurality of POL regulators via the serial data bus. The digital data includes programming data for programming the plural filter coefficients. The system controller further comprises a user interface adapted to receive the programming data therefrom.

Method and system for communicating filter compensation coefficients for a digital power control system

This book is for RF Engineers and, in particular, those engineers focusing mostly on RF systems and RFIC design. The author develops systematic methods for RF systems design, complete with a comprehensive set of design formulas. Its focus on mobile station transmitter and receiver system design also applies to transceiver design of other wireless systems such as WLAN. This comprehensive reference work covers a wide range of topics from general principles of communication theory, as it applies to digital radio designs to specific examples on implementing multimode mobile systems.

/pdf/rf-system-design-of-transceivers-for-wireless-communications-4xdg3wr5gp.pdf

RF System Design of Transceivers for Wireless Communications

A review of photodetectors for optical detection in biological applications is presented. The intent is to provide an overview of the performance metrics and trade-offs among popular photodetectors in order to facilitate an easier match among the photodetector, biological stimulus, and optical pathway. The characteristics and nonidealities of fluorescent and phosphorescent reporters, and the properties of optical components such as filters, lenses, and light sources, are reviewed. By accounting for sources of noise in these components, it is shown how to determine metrics for the optical system that can then be converted to photodetector metrics. Defined photodetector metrics include the quantum efficiency, responsivity, noise-equivalent power, detectivity, gain, dark current, response time, and noise spectrum. The operating principles and performance trade-offs of photodetectors are reviewed, and emphasis is placed on photodetectors for integrated compact systems. Top commercial candidates for photodetectors for detecting light emitted from reporters are the photomultiplier tube, avalanche photodiode, and charge-coupled device. Focus is placed on new developments in complementary metal-oxide-semiconductor structures that can provide low-cost, low-power, and low-voltage alternatives to traditional approaches to biological imaging. Reviewed device structures are presented in the context of supporting the development of laboratory-based instruments and compact fully-integrated systems.

https://www.bioee.ee.columbia.edu/courses/upload/Bibliography/yotter2003.pdf?origin=publication_detail

A review of photodetectors for sensing light-emitting reporters in biological systems

A multimode communications device includes an RF section and an analog-to-digital converter (ADC) located in a receive path between the RF section and a baseband section. The ADC includes a programmable signal converter core operable to perform ADC functions on a received RF signal in accordance with different types of mobile communication device operational modes, and further includes a multimode control function for programming the signal converter core as a function of a currently selected operational mode. The programmable signal converter core preferably includes a sigma-delta modulator, and a signal analysis function is provided for analyzing the received RF signal for dynamically programming the converter core to adapt to temporary signal and interference conditions by increasing or decreasing the performance of the signal converter. The signal analysis function may be embodied as a decimation filter having an input coupled to an output of the modulator, or by a digital signal processor forming a portion of a baseband section. The programmable signal converter core may be programmed to change the number of bits used by the sigma-delta modulator and/or a loop filter transfer function and loop filter coefficients, or a number of quantizer levels, or decimator coefficients and word width. The sigma-delta modulator bias currents may also be changed, as may a selected type of dynamic element matching function, each as a function of the selected mode. Other operational criteria that can be changed include the sigma-delta modulator oversampling ratio and/or a change from a switched capacitor to a resistor-capacitor circuit technique, or vice versa.

Adaptive sigma-delta data converter for mobile terminals

An integrated receiver channel for a pulsed time-of-flight (TOF) laser rangefinder has been designed and tested. The bandwidth of the receiver channel is 170 MHz, the transimpedance can be controlled in the range from 1.1 k/spl Omega/ to 260 k/spl Omega/, and the input-referred noise is /spl sim/6 pA//spl radic/Hz. The distance measurement accuracy is /spl plusmn/4.7 mm (average of 10000 measurements), taking into account walk error (input signal amplitude varies in the range 1:624) and jitter. A considerable increase in the input dynamic range of the receiver has been achieved by placing an integrated current buffer with variable attenuation between the external photodetector and the transimpedance preamplifier. Integrated electronic gain control structures together with the small size and low power consumption achieved by the use of full custom integrated technology considerably simplifies rangefinding devices for many applications. The circuit was implemented in an 0.8-/spl mu/m BiCMOS process.

A wide dynamic range receiver channel for a pulsed time-of-flight laser radar

An audio path is constructed to include a multi-bit sigma-delta converter for converting an N-bit digital input to an n-bit output representing an over-sampled, lower resolution n-bit version of the N-bit digital input; a formatter for converting the n-bit output to an m signal output (e.g., as a thermometer code, a SDM format or a PWM format); an m-by-m switching matric for receiving the m output signals and for reordering the m output signals, m class-D drivers individual ones of which are driven by one of the reordered m output signals for driving one of m speakers; and a dynamic element matching (DEM) block coupled to the switching matric for controlling the reordering of the m output signals driving the m class-D drivers for spreading the distortion due at least to driver-speaker pair mismatch to wide band noise. The DEM may operate to generate white noise, or it may generate shaped (colored) noise.

Method and apparatus for implementing a class D driver and speaker system

An integrated receiver channel of a pulsed time-of-flight (TOF) laser rangefinder for fast industrial measurement applications with the measurement accuracy of a few centimeters in the measurement range from /spl sim/1 m to /spl sim/30 m to noncooperative targets was developed. The receiver channel consists of a fully differential transimpedance amplifier channel, a peak detector, an rms meter and a timing discriminator. In this particular application there is no time to measure the received signal strength beforehand and it is not predictable from previous measurements, so a leading edge timing discriminator with a constant threshold voltage was used. The amplitude of the received pulse is measured with a peak detector and the amplitude information is used to compensate for the resulting walk error. The measured bandwidth of the receiver channel is 250 MHz, the maximum transimpedance 40k/spl Omega/ and the input-referred noise /spl sim/7pA//spl radic/Hz (C/sub photodiode/=2 pF). The timing detection accuracy of the receiver is better than /spl plusmn/35 mm in a single-shot measurement in a dynamic range of 1:4000 and a temperature range of 0/spl deg/C to +50/spl deg/C.

A 250-MHz BiCMOS receiver channel with leading edge timing discriminator for a pulsed time-of-flight laser rangefinder

An N-level quantizer circuit (14) has an analog input terminal and N-1 digital output terminals, and includes a sampling circuit (SW samp) coupled to the input terminal for providing a sampled input voltage signal; at least one preamplifier stage (14A) for converting the sampled input voltage signal to a current signal and providing an amplified sampled input signal; and N-1 comparator stages (14B) each having an input coupled to an output of the at least one preamplifier stage (14A) and sharing the input current equally. Individual ones of the N-1 comparator stages (14B) operate to compare the amplified sampled signal to an associated one of N-1 reference signals. The quantizer (14) further includes N-1 latches (14C), individual ones of which latch an output state of one of the N-1 comparators and have an output coupled to one of the N-1 digital output terminals of the quantizer circuit (14).

Low capacitance, low kickback noise input stage of a multi-level quantizer with dithering and multi-threshold generation for a multi-bit sigma-delta modulator

Tarmo Ruotsalainen

Papers

Adaptive sigma-delta data converter for mobile terminals

A wide dynamic range receiver channel for a pulsed time-of-flight laser radar

Method and apparatus for implementing a class D driver and speaker system

A 250-MHz BiCMOS receiver channel with leading edge timing discriminator for a pulsed time-of-flight laser rangefinder

Low capacitance, low kickback noise input stage of a multi-level quantizer with dithering and multi-threshold generation for a multi-bit sigma-delta modulator