Blackman's Theorem

	Blackman's Theorem Blackman's theorem is a general procedure for calculating the change in an impedance due to feedback in a circuit. It was published by Ralph Beebe Blackman in 1943, was connected to signal-flow analysis by John Choma, and was made popular in the extra element theorem by R. D. Middlebrook and the asymptotic gain model of Solomon Rosenstark. Blackman's approach leads to the formula for the impedance ''Z'' between two selected terminals of a negative feedback amplifier as Blackman's formula: :Z = Z_D \frac \ , where ''ZD'' = impedance with the feedback disabled, ''TSC'' = loop transmission with a small-signal short across the selected terminal pair, and ''TOC'' = loop transmission with an open circuit across the terminal pair. The loop transmission also is referred to as the return ratio. Blackman's formula can be compared with Middlebrook's result for the input impedance ''Zin'' of a circuit based upon the extra-element theorem: :Z_ = Z^_ \left \frac\right/math> where: :Z\ is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Ralph Beebe Blackman Ralph Beebe Blackman (August 29, 1904 – May 24, 1990) was an American mathematician and engineer who was among the pioneers of the information age along with Claude E. Shannon, Hendrik Wade Bode, and John Tukey. Blackman graduated from the California Institute of Technology in 1926 and started work at Bell Labs, Bell Laboratories the same year. His early research were in the fields of hearing, acoustics and mechanical filters. Later he focused on applied mathematics, specifically Network analysis (electrical circuits), linear networks and Negative feedback amplifier, feedback amplifiers. Starting in 1940, Blackman worked on data smoothing for Fire-control system#Anti-aircraft fire control, anti-aircraft fire control systems. In 1963 Blackman was elected an Institute of Electrical and Electronics Engineers#Membership and member grades, IEEE Fellow. Books * * Patents * * * * * * * * * See also Blackman's theorem References California Ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Signal-flow Graph A signal-flow graph or signal-flowgraph (SFG), invented by Claude Shannon, but often called a Mason graph after Samuel Jefferson Mason who coined the term, is a specialized flow graph, a directed graph in which nodes represent system variables, and branches (edges, arcs, or arrows) represent functional connections between pairs of nodes. Thus, signal-flow graph theory builds on that of directed graphs (also called digraphs), which includes as well that of oriented graphs. This mathematical theory of digraphs exists, of course, quite apart from its applications. i SFGs are most commonly used to represent signal flow in a physical system and its controller(s), forming a cyber-physical system. Among their other uses are the representation of signal flow in various electronic networks and amplifiers, digital filters, state-variable filters and some other types of analog filters. In nearly all literature, a signal-flow graph is associated with a set of linear equations. Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	John Choma (professor) John Choma was Professor and Chair of Electrical Engineering-Electrophysics at the University of Southern California. Choma held B.S., M.S., and Ph.D. degrees in electrical engineering from the University of Pittsburgh The University of Pittsburgh (Pitt) is a public state-related research university in Pittsburgh, Pennsylvania. The university is composed of 17 undergraduate and graduate schools and colleges at its urban Pittsburgh campus, home to the universit .... His graduate theses were: * "Design of a Transistor Phasemeter," M.S. Thesis, University of Pittsburgh, 1965. * "Stability Analysis of Class C Transistor Amplifiers," Ph. D. Dissertation, University of Pittsburgh, 1969. Choma joined the USC faculty in 1980. He taught undergraduate and graduate courses in Network analysis (electrical circuits), electrical circuit theory, Electronic filter, filters, and Integrated circuit design#Analog design, analog integrated electronics, and advised industry in subjects relating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]