Inherent Gain Research Articles

Noise characteristics of a microchannel plate x-ray image intensifier.

The noise performance of an experimental microchannel plate x-ray image intensifier has been evaluated. The intensifier, constructed for use with photons of energies between 20 and 150 keV, uses an MCP as the photon-to-electron converter. The influence of noise was determined by analysis of the optical-density fluctuations of a photograph of the viewing screen of the intensifier when the conversion layer was exposed to between 1 and 60 mR. Additionally, the contrast-detail performance of the experimental device was determined. The influence of both stochastic noise, due to quantum mottle and pulse-height variations, and structural noise, due to fluctuations in inherent gain from point to point, have been considered by using a model that adds these components.

Involvement-Associate Member Forum/Metropolitan Section-Speaks Out

There are 900 Associate Members in the Met Section, equal to 30% of the total membership. The Associate Member Forum offers a means to those young engineers starting out in the civil engineering profession to work together in developing a program of activities both professional and social influencing many of these associate members, and future members enrolled in the local engineering schools. There is also the inherent gain for the active individual as a result of the hard work in planning, organizing, and carrying out the programs of AMF. The development of the individual professionally as he moves up the ladder from AMF to Met Section to National Office in ASCE begins with that first commitment to “get active”, and the “follow through” it requires to accomplish a job “well done.”

An integrated linear-transconductance analog multiplier

This paper describes a new solid-state, monolithic inte grated analog multiplier, based on the controlled-trans conductance principle that is designed for high speed, high accuracy, and excellent linearity. A novel differ ential amplifier circuit permits cancellation of undesired nonlinearities, and carefully matched device geometries account for the good accuracy of the new multiplier. With an inherent voltage gain of A v = 1/10, the multi plier will provide a ± 10 V output at ± 10 mA with linearity approaching 0.1 % at 100 Hz. The multiplier package may be used in conjunction with an external operational amplifier and external resistors, and offers the advantages of monolithic construction (low cost, ex cellent temperature tracking) with the precision of ad justable-parameter, discrete construction.

Magnetic amplifier binary-to-analog conversion

The problem of digital to analog conversion occurs frequently in systems using digital computers. Where power gain is needed, where a high degree of accuracy must be maintained, and where speed of response is not a limiting factor, magnetic amplifiers have special utility in decoding of digital information. Based on the saturable reactor with multiple control windings proportioned in a binary scale, a magnetic amplifier circuit has been devised to convert a 10-digit parallel binary-coded input to an analog voltage ranging from 0 to 102.3 volts average with an accuracy of better than one part in a thousand. With the 10-digit input, three saturable reactors are used for the basic conversion to analog and a subsequent stage of self-balancing magnetic amplifier provides additional gain to drive a servomagnetic amplifier. In the over-all conversion circuit, the inherent feedback, signal mixing, and power gain capabilities of magnetic amplifiers appear to result in a simpler and more reliable circuit than could be achieved with other techniques.1 This paper discusses the application of magnetic amplifiers in a digital to analog conversion.

Research of the 21 CM radiation at Agassiz Station.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Research of the 21 CM radiation at Agassiz Station. Bok, Bart J. ; Ewen, Harold I. Abstract The present paper by A. E. Lilley and D. S. Heeschen reports on the progress made to date on the Radio Astronomy Project at Agassiz Station. A 24-foot parabolic antenna operating in conjunction with a comparison radiometer has been used to record the profiles of the 21 cm line of neutral hydrogen. The electronic equipment is essentially a double conversion superheterodyne microwave receiver. The comparison radiometer feature is accomplished by separately detecting two portions of the received spectrum after separation by a double band pass filter network. By continuously comparing these two rectified noise powers in a balanced recorder, the inherent gain fluctuations of the overall equipment are minimized to a level well below the detectable difference produced by the presence of a hydrogen signal in one. To date, the Agassiz Station Project has concentrated its efforts upon analyses of regional surveys of 21 cm profiles along the Milky Way. Two projects have already been completed, the first that of Lilley, who has been primarily concerned with the study of interstellar hydrogen associated with cosmic dust in the dark nebulae complex in Taurus, and the second that of Heeschen, who has studied certain astrophysical problems related to the line profiles for the section of the galactic center. The total number of centers for these two projects combined is about two hundred; for each center a minimum of four scans was considered necessary. Several programs are now under way at Agassiz Station. Thomas A. Matthews is studying the sections of the Milky Way near 1 = 800 and 1 = 1150, with several connecting strips and extensions at galactic latitudes b = - 150, 00 and + ISo, and with, for each section, one strip running from b = - 600 to +600. This section was selected because of the interesting feature that the separation between the two principal spiral arms is very marked in the profiles. Three other sections of the Milky Way are under investigation. David S. Heeschen has already obtained profiles for a number of centers in Cygnus and will complete this program in collaboration with Campbell M. Wade. Wade is investigating the variation in the line profiles at b = +150 for the connection between the Ophiuchus and Cygnus centers. Finally, T. K. Menon is concentrating on the section from Gemini, thr~ugh Orion and Monoceros to Canis Major, with special emphasis on the region of the Orion Nebula. The Agassiz Station Project has been supported by a gift from a friend of the Station and through two grants from the National Science Foundation. John A. Campbell is the electronic engineer on the project. Harvard College Observatory, Cambridge, Mass. Publication: The Astronomical Journal Pub Date: August 1954 DOI: 10.1086/107070 Bibcode: 1954AJ.....59Q.318B full text sources ADS |