摘要:

The basic lock-in amplifier model will be briefly surveyed in order to present a few critical guidelines for its usage in analytical spectrometry. Expressions for the impulse response, time variant impulse response, the variant transfer function, the power transfer function, and the time variant time autocorrelation function of the lock-in amplifier are given. Figures of merit for the lock-in including the noise bandwidth and the signal-to-noise-improvement ratio are also given. The general conditions which must be met for successful shot noise limited application of lock-in detection are presented as well as how these conditions are applied to actual spectrometric systems.

ISSN:1073-9149    

DOI:10.1080/10739148608543618

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A quantitative boxcar model is presented in this paper. Expressions for the time variant impulse response, the time variant transfer function, and the time variant time autocorrelation function of the boxcar are given. Figures of merit for the boxcar including the noise bandwidth and the signal-to-noise-improvement ratio are given. The boxcar signal-to-noise expressions are then applied to the determination of the optimum integration limits for six standard pulse shapes.

ISSN:1073-9149    

DOI:10.1080/10739148608543619

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The construction of a microcomputer controlled pulsed amperometric detector system is described. It includes a potentiostat, a flow-through cell and a sample injection unit. The microcomputer generates the appropriate waveform of the applied potential and controls the overall sequence of the measurement. The system is suitable for general studies on the detection of various classes of organic compounds with the pulsed amperometric technique. The detectability of various hydroxycompounds has been studied.

ISSN:1073-9149    

DOI:10.1080/10739148608543620

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A dedicated portable fluorimeter, for use with fiber optic chemical sensors (FOCS) has been designed, constructed, tested, and calibrated. This represents a major advance in the development of a FOCS system suitable for in-field use. The portable fluorimeter uses an incandescent lamp, instead of a laser, for FOCS excitation and a photodiode, in place of a photomultiplier tube for detecting the fluorescence signal. It uses an optical system which is internally connected to a unitized optical block by 600 μm core optical fibers, to minimize alignment problems and increase overall system ruggedness. The system noise is less than .1.5 mV and the long-term drift is less than ±2 mV/hour. Measurements of organochloride were made at concentrations as low as 80 parts-per-billion with a signal to noise ratio of 40:1.

ISSN:1073-9149    

DOI:10.1080/10739148608543621

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148608543622

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148608543623

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor