Chapter 17 “Transforms” Rin to the Value Rgen (As Seen by the Generator) and at the Same Time Nullifies the Reactance
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Vintage Radio
VINTAGE RADIO Building a vintage radio "replica" Have you always wanted a 1920s or 1930s lacquer finish of some sort. Second, a glance at the front panel reveals that "cathedral" style radio. They're as scarce as these sets can receive FM transmis- sions as well as AM. In reality, FM hens' teeth these days - or are they? If you didn't get under way in Australia un- can't get an original, what about one of the til well after the era that the "replica" is supposed to represent. many replicas now coming onto the market? However, it's not until you expect the "insides" of such radios that you From time to time, "replicas" of ites but of course, they're not true realise just how far away they are early radio sets appear in catalog ad- replicas. First, the cabinets are noth- from being a true replica of the era. vertisements from various electronics ing like the those from the 20s, 30s Hidden inside the cabinet will be a and electrical retailers. Consoles and and 40s, usually being made from small transistor radio and that's hardly cathedral sets seem to be the favour- cheap ply or particle board with a something that was around in the 1920s or 1930s! So these sets are in no way an accu- rate copy or replica of any early radio. The fact is, there are very few genu- ine 1920s (and not many more 1930s) sets now available on the market. Many collectors will never own ra- dios of this vintage. -
1994-11: Browning-Drake
Vii luta gic IRaidl iio by PETER LANKSHEAR The Browning-Drake receiver One of the best remembered radio names from the 1920's is 'Browning-Drake', a receiver which combined simplicity with what for its time was a rate performance. While most of its contempo- raries had production lives of little more than a year, the Browning-Drake design was popular for much of the decade. As with the IBM personal computer'. it. recently, there were also more 'clones' made by others than the official versions... By the outbreak of World War I, valve cluding them in tuned circuits coupling The alternative method, and of course receiver technology had advanced to the the valves. However the tuned RF ampli- the ultimate solution to many difficulties stage where stable detection and low fre- fier then ran into another problem. Tri- was the superheterodyne, attributed by quency amplification were possible. ode valves have sufficient inter-ekctrode Americans to work done in 1918 by Ma- However there were limitations to the capacitance that with tuned circuits con- jor Edwin Armstrong of the US Army. sensitivity and selectivity of the grid leak nected to both anode and grid, there is While much credit is due to Armstrong, it detectors that had become standard. sufficient energy transferred internally is now clear that the original concept of The newly discovered regeneration back to the grid to cause them to become the superhet was an international effort, helped, but it became clear that the only vigorous oscillators. with much of the early work being done way to improve receiver sensitivity was Initially there were two solutions. -
Man of High Fidelity
Man of High Fidelity: EDWIN HOWARD ARMSTRONG A Biography – By Lawrence Lessing With a new forward by the author Page iii Pratt DISCLAIMER DISCLAIMER TO THIS SCANNED AND OCR PROCESSED COPY This PDF COPY is for use at Pratt Institute for Educational Purposes Only I affirm that sufficient print copies of the original Bantam Book Paperback are in stock in ARC E-08 that would more than adequately cover a full class use of the text. HOWEVER, due to the fact that the 1969 text is no longer in publication, complicated by the fact that these copies are forty-four (44) years old and in a very fragile condition, this PDF version of the text was created for student use in the Department of Mathematics and Science. - Professor Charles Rubenstein, January 2013 Man of High Fidelity: Edwin Howard Armstrong EDWIN HOWARD ARMSTRONG Was the last – and perhaps the least known – of the great American Inventors. Without his major contributions, the broadcasting industry would not be what it is today, and there would be no FM radio. But in time of mushrooming industry and mammoth corporations, the recognition of individual genius is often refused, and always minimized. This is the extraordinary true story of the discovery of high fidelity, the brilliant man and his devoted wife who battled against tremendous odds to have it adopted, and their long fight against the corporations that challenged their right to the credit and rewards. Mrs. Armstrong finally ensured that right nearly ten years after her husband’s death. Page i Cataloging Information Page This low-priced Bantam Book has been completely reset in a type face designed for easy reading, and was printed from new plates. -
P020190719536109927550.Pdf
Integrated Circuits and Systems Series Editor Anantha Chandrakasan, Massachusetts Institute of Technology Cambridge, Massachusetts For other titles published in this series, go to www.springer.com/series/7236 Eric Vittoz Low-Power Crystal and MEMS Oscillators The Experience of Watch Developments Eric Vittoz Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland [email protected] ISSN 1558-9412 ISBN 978-90-481-9394-3 e-ISBN 978-90-481-9395-0 DOI 10.1007/978-90-481-9395-0 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2010930852 © Springer Science+Business Media B.V. 2010 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Cover design: Spi Publisher Services Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) To my wife Monique Contents Preface ...................................................... xi Symbols ..................................................... xiii 1 Introduction ............................................. 1 1.1 Applications of Quartz Crystal Oscillators. ................ 1 1.2 HistoricalNotes ...................................... 2 1.3 TheBookStructure................................... -
Parasitic Oscillation (Power MOSFET Paralleling)
MOSFET Parallening (Parasitic Oscillation between Parallel Power MOSFETs) Description This document explains structures and characteristics of power MOSFETs. © 2017 - 2018 1 2018-07-26 Toshiba Electronic Devices & Storage Corporation Table of Contents Description ............................................................................................................................................ 1 Table of Contents ................................................................................................................................. 2 1. Parallel operation of MOSFETs ........................................................................................................... 3 2. Current imbalance caused by a mismatch in device characteristics (parallel operation) ..................... 3 2.1. Current imbalance in steady-state operation ......................................................................................... 3 2.2. Current imbalance during switching transitions ............................................................................. 3 3. Parasitic oscillation (parallel operation) ............................................................................................... 4 3.1. Gate voltage oscillation caused by drain-source voltage oscillation ........................................... 4 3.2. Parasitic oscillation of parallel MOSFETs .......................................................................................... 5 3.2.1. Preventing parasitic oscillation of parallel MOSFETs .............................................................................. -
Parasitic Oscillation and Ringing of Power Mosfets Application Note
Parasitic Oscillation and Ringing of Power MOSFETs Application Note Parasitic Oscillation and Ringing of Power MOSFETs Description This document describes the causes of and solutions for parasitic oscillation and ringing of power MOSFETs. © 2017 - 2018 1 2018-07-26 Toshiba Electronic Devices & Storage Corporation Parasitic Oscillation and Ringing of Power MOSFETs Application Note Table of Contents Description ............................................................................................................................................ 1 Table of Contents ................................................................................................................................. 2 1. Parasitic oscillation and ringing of a standalone MOSFET .......................................................... 3 2. Forming of an oscillation network ....................................................................................................... 3 2.1. Oscillation phenomenon ..................................................................................................................... 3 2.1.1. Feedback circuit (positive and negative feedback) ......................................................................... 4 2.1.2. Conditions for oscillation ...................................................................................................................... 5 2.2. MOSFET oscillation .............................................................................................................................. 5 2.2.1. -
A Practical Neutrodne Receiver by ALLAN T
Radio News for January, 1924 899 A Practical Neutrodne Receiver By ALLAN T. HANSCOM This article explains the action of the neutrodyne circuit in a manner which can be grasped by the novice. Its formation is described stage by stage, followed by complete constructional details for the building of a receiver of this type. on which the secondary coil is wound. It is difficult to buy one tube to fit inside an- other in this manner, but it can be overcome by sawing a piece of tube /" wide length- wise from the same tubing. Then when it is wound, the wire will draw it to a smaller diameter whereupon it may be slid into place inside the full sized tube. It is very im- portant that these transformers be mounted Insulated wire fig. 2 /w/sted together A One -Stage Radio Frequency Amplifier and a Non- Regenerative Detector, the Respective Secondary Circuits of Which Are Tuned by Means of Variable Condensers. IT is unfortunate that so many good cir- the neutrodyne after we add the neutralizing cuits are labeled with such formidable condensers which will be considered later. titles. The name "neutrodyne" is usu- In Fig. 3, there are two stages of radio ally enough to scare the average radio frequency amplification and the detector, fan. A neutrodyne circuit, as commer- each stage being tuned by a variable conden- cially developed, is, however, a great deal ser in the grid circuit. This circuit would more simple to understand than the regen- give wonderful results if it were not for the erative or reflex circuit. -
Self-Oscillation
Self-oscillation Alejandro Jenkins∗ High Energy Physics, 505 Keen Building, Florida State University, Tallahassee, FL 32306-4350, USA Physicists are very familiar with forced and parametric resonance, but usually not with self- oscillation, a property of certain dynamical systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the driving force is controlled by the oscillation itself so that it acts in phase with the velocity, causing a negative damping that feeds energy into the vi- bration: no external rate needs to be adjusted to the resonant frequency. The famous collapse of the Tacoma Narrows bridge in 1940, often attributed by introductory physics texts to forced resonance, was actually a self-oscillation, as was the swaying of the London Millennium Footbridge in 2000. Clocks are self-oscillators, as are bowed and wind musical instruments. The heart is a \relaxation oscillator," i.e., a non-sinusoidal self-oscillator whose period is determined by sudden, nonlinear switching at thresholds. We review the general criterion that determines whether a linear system can self-oscillate. We then describe the limiting cycles of the simplest nonlinear self-oscillators, as well as the ability of two or more coupled self-oscillators to become spontaneously synchronized (\entrained"). We characterize the operation of motors as self-oscillation and prove a theorem about their limit efficiency, of which Carnot's theorem for heat engines appears as a special case. We briefly discuss how self-oscillation applies to servomechanisms, Cepheid variable stars, lasers, and the macroeconomic business cycle, among other applications. Our emphasis throughout is on the energetics of self-oscillation, often neglected by the literature on nonlinear dynamical systems. -
Journal Vol 9-X 1985
Ctil?~ ()fflclal JI ~()IU IV~ A\ IL JAN - MAR 1985 CALIFORNIA HISTORICAL RADIO SOCIETY PRESIDENT: NORMAN BERGE SECRETARY: BOB CROCKETT TREASURER: JOHN ECKLAND EDITOR: HERB BRAMS PHOTOGRAPHY: GEORGE DURFEY CONTENTS CLUB NEWS •••••••••••••••••••••••••••••••••••••••••••••••• • . l THE SUPERHETERODYNE RECEIVER ••••••••••••••••••••••••••••••• 3 WHAT KIND OF COLLECTOR ARE YOU? •••••••••••••••••••••••••• 20 BALLAST TUBES AND RESISTANCE LINE CORDS ••••••••••••••••••• 21 ADVERTISEMENTS •••••••••••••••••••••••••••••••••••••••••••• 24 THE SOCIETY ll\e California Historical Radio Society is a non-profit corporation chartered in 1974 to promote the preservation of early radio equipment and radio broadcasting. CHRS provides a meditDD for members to exchange infor mation on the history of radio with emphasis on areas such as collecting, cataloging and restoration of equipment, literature. and programs. Regular swap meets are scheduled four times a year. For further information, write the California Historical Radio Society, P. O. Box 1147, Mountain View , CA 94042-114 7. THE JOURNAL ll\e official Journal of the California Historical Radio Soc i ety i a published six times a year and is furnished free to all members. Articl e• for the Journal are solicited from all members. Appropriate subjects include information on early radio equipment. personalities, or broadcasts, restoration hints, photographs, ads, etc. Material for the Journal should be sulrnitted to the Editor, Herb Brams, 2427 Durant #4, Berkeley, CA 94704. MEMBERSHIP Membership correspondence should be addressed to the Treasurer, John Eckland, 969 Addison Ave., Palo Alto, CA 94301. CHRS SWAP MEETS CHRS swap meets have tentatively been set for the following dates: June 1, Aug. 31, and Nov. 9 at Foothill College. Notices will be sent if these dates are changed. -
Alignment and Neutralization of the Early Ac Trf & Neutrodyne Receivers
ALIGNMENT AND NEUTRALIZATION OF THE EARLY AC TRF & NEUTRODYNE RECEIVERS by Lane S. Upton 3788 S. Loretta Dr. Salt Lake City, UT 84106-2956 For a radio to work as it was originally designed, it must be in proper alignment. This means that at any single point on the dial all tuned circuits must be at resonance and the dial calibration should be correct. In the case of neutrodyne receivers, additional steps must be taken to assure that each neutralized amplifier stage is adjusted properly. This will assure that the full gain can be realized. The purpose of this article is to provide a detailed review of the steps necessary to completely align these receivers. Much was written on this subject when the radios were relatively new, but it was all directed toward working on a "modern" receiver only a few years old. Today, we must look at warped variable condensers, worn wiper contacts, poor ground connections, coil windings that have shifted position, incorrectly positioned coils, loose shield cans, and many other problems brought about by age and abuse. The time spent doing a complete alignment will typically result in a radio with greatly improved selectivity and sensitivity. This is especially true at the lower frequency portion of the dial. Preliminary Work The initial work on a set must include inspection of all the components that will affect alignment. This should not be limited to the variable condenser and coils, but must include all other items that can have any effect. The following steps represent a basic outline of the preliminary work that should be carried out. -
Preventing Gan Device VHF Oscillation APEC 2017
Preventing GaN Device VHF Oscillation APEC 2017 Zan Huang, Jason Cuadra APEC 2017 | 1 Parasitic oscillation • Parasitic oscillation can occur in any switching circuit with fast- changing voltage and current that stimulate a parasitic LC network • The oscillation becomes sustained when positive feedback with gain is present • The feedback could be through parasitic capacitance, parasitic inductance, shared or coupling inductance, etc. • Together with the device gain in the linear region, creates an oscillator • Preventing oscillation in fast-switching GaN devices is more challenging than in silicon due to • Faster dv/dt and di/dt • Higher transconductance • Violent sustained VHF oscillation (50-200MHz) will cause destruction APEC 2017 | 2 Sustained oscillation • In a half-bridge circuit with high speed devices on both the high and low side, there are three steps that yield sustained oscillation on the high-side device during low-side device turn-on, and vice versa Note: Sustained oscillation can occur even in a single-ended circuit, with very fast switching, e.g. a boost converter using a FET+diode; the analysis is similar to a half-bridge APEC 2017 | 3 Step 1: VGS change due to high dv/dt • During low-side turn-on, the high-side FET is subjected to a large positive dv/dt, which couples through CGD to increase VGS, (“Miller effect”) reducing its off-voltage margin against gate threshold VTH • To counter this, Transphorm devices are designed with a low ratio of CGD to CGS to minimize the Miller effect APEC 2017 | 4 Step 2: VGS change due -
Radio Broadcast
RADIO BROADCAST WILLIS KINGSLEY WING, Editor OCTOBER, 1927 KEITH HENNEY EDGAR H. FELIX Vol. XI, No. 6 Director of the Laboratory Contributing Editor =* AMO7S[G OTHER THINGS. - - - - Cover Design From a Design by Harvey Hopkins Dunn MUCH is now being accomplished in the complete set SOfield that beginning with this issue, RADIO BROADCAST Station the Frontispiece The Most Powerful Broadcasting in World 340 will devote much of its space to reflecting the technical and other advances being made. The policy of this magazine remains as Now You Can Receive Radio Pictures - - Keith tienney 341 before, to present the news of radio surrounded by as much as of what the technical radio worker refers to as The March of Radio An Editorial possible "dope." Interpretation 344 And much "dope" there is in this complete set side of radio as Modern Radio Receivers are a Good Invest- The of Direct on the Danger Advertising Air articles which will in issues will ment The Month in Radio many appear following strikingly demonstrate. In all the other fields of radio endeavor Listening to World-Wide Broadcasting is Licenses and What They Mean which Near The Columbia Broadcasting Chain RADIO BROADCAST has covered heretofore the construction A Profound Study of Radio Law of radio receiving apparatus, laboratory experiments, short- - wave communication, from the technical and The 1928 "Hi'Q" Has an Extra R. F. Stage John B. Brennan 348 broadcasting program side, and many others which we have covered to Manufactured Receivers for the Coming Season - - - 351 the satisfaction of our readers, RADIO BROADCAST will be as active as before.