The Transistor Amplifier
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HF Linear Amplifiers
- • - • --• --•• • •••- • --••• - • ••• •- • HFHF LinearLinear AmplifiersAmplifiers Basic amplifier concepts, types & operation Adam Farson VA7OJ Tube Amplifiers Solid-State Amplifiers 1 October 2005 NSARC HF Operators – HF Amplifiers 1 BasicBasic LinearLinear AmplifierAmplifier RequirementsRequirements - • - • --• --•• • •••- • --••• - • ••• •- • ! Amplify the exciter’s RF output (by 10 dB or more). ! Provide a means of correct matching to load. ! Amplify complex signals such as SSB with minimum distortion (maximum linearity). ! Transmit a spectrally-pure signal. ! Assure a safe operating environment. 1 October 2005 NSARC HF Operators – HF Amplifiers 2 BasicBasic AmplifierAmplifier TypesTypes - • - • --• --•• • •••- • --••• - • ••• •- • ! Tube, grounded-grid triode (cathode-driven) – most popular. Some designs use tetrodes. ! Tube, grounded-cathode tetrode (grid-driven) – less common, but growing in popularity. ! Solid-state, BJT (junction transistors) – 500W or 1 kW. ! Solid-state, MOSFET – typically 1 kW. 1 October 2005 NSARC HF Operators – HF Amplifiers 3 Grounded-Grid Triode Amplifier showing pi-section input & output networks - • - • --• --•• • •••- • --••• - • ••• •- • Input network: C1-L1-C2 Plate feed circuit: RFC2-C5 Output network: C6-L2-C7 Plate tuning: C6 Loading: C7 Input impedance of grounded-grid triode amplifier Is low, complex, and also non-linear (decreases at onset of grid current). Tuned input network tunes out reactive (C) component, and also linearizes tube input impedance via flywheel effect. Cathode choke RFC1 provides DC return path for plate feed, and allows cathode to “float” at RF potential. Heater (or filament of directly-heated tube) powered via bifilar RF choke. Pi-output network matches tube load resistance to antenna, RF drive power added to output. Amplifier can operate in Class AB1 (no grid current) or AB2 (some grid current). 1 October 2005 NSARC HF Operators – HF Amplifiers 4 TubesTubes forfor GroundedGrounded--GridGrid AmplifiersAmplifiers - • - • --• --•• • •••- • --••• - • ••• •- • • Directly-heated glass triode (e.g. -
High Efficiency Power Amplifier for High Frequency Radio Transmitters
High Efficiency Power Amplifier for High Frequency Radio Transmitters M.Vasic, 0. Garcia, J.A. Oliver, P. Alou, D. Diaz, J.A. A.Gimeno, J.M.Pardo, C.Benavente, F.J.Ortega Cobos Radio Engineering Group (GIRA) Centra de Electronica Industrial (CEI) Universidad Politecnica de Madrid Universidad Politecnica de Madrid Madrid, Spain Madrid, Spain [email protected] Abstract— Modern transmitters usually have to amplify and One of the techniques that offer high efficiency and high transmit complex communication signals with simultaneous linearity is the Kahn's technique or Envelope Elimination and envelope and phase modulation. Due to this property of the Restoration (EER) technique [3]. This method proposes transmitted signal, linear power amplifiers (class A, B or AB) linearization of highly efficient, but nonlinear power amplifier are usually employed as a solution for the power amplifier stage. (class E or D) by modulation of its supply voltage. The These amplifiers have high linearity, but suffer from low modulation of the supply voltage is done through an envelope efficiency when the transmitted signal has high peak-to-average amplifier according to the reference signal that is proportional power ratio. The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF to the envelope of the transmitted signal, while the phase transmitters, by combining highly efficient, nonlinear RF modulation of the transmitted signal is conducted through the amplifier (class D or E) with a highly efficient envelope amplifier nonlinear amplifier. The basis for EER is the equivalence of in order to obtain linear and highly efficient RF amplifier. -
Simple Blocking Oscillator Performance Analysis for Battery Voltage Enhancement
Journal of Mobile Multimedia, Vol. 11, No.3&4 (2015) 321-329 © Rinton Press SIMPLE BLOCKING OSCILLATOR PERFORMANCE ANALYSIS FOR BATTERY VOLTAGE ENHANCEMENT DEWANTO HARJUNOWIBOWO ESMART, Physics Education Department, Sebelas Maret University, Indonesia [email protected] RESTU WIDHI HASTUTI Physics Education Department, Sebelas Maret University, Indonesia [email protected] KENNY ANINDIA RATOPO Physics Education Department, Sebelas Maret University, Indonesia [email protected] ANIF JAMALUDDIN ESMART, Physics Education Department, Sebelas Maret University, Indonesia [email protected] SYUBHAN ANNUR FKIP MIPA, Lambung Mangkurat University, Indonesia An application Blocking Oscillator (BO) on a battery to power a system LED lamp light detector has been built and compared with a standard system used phone cellular adapter as the power supply. The performance analysis was carried out to determine the efficiency of the blocking oscillator and its potency to be adopted in an electronic appliance using low voltage and current from a battery. Measurements were taken using an oscilloscope, a multimeter, and a light meter. The results show that the system generates electrical pulses of 1.5 to 7.6 VDC and powering the system normally. The system generates 3.167 mW powers to produce the intensity of 176 Lux. On the contrary, the standard system needs 1.8mW to produce 5 Lux. A LED usually takes at least 60mW to get 7150 Lux. Therefore, the system used a simple blocking oscillator seems potential to provide high voltage for powering electronic appliances with low current. Key words: blocking oscillator, characteristic, efficiency, LED, pulse 1 Introduction A design of circuit based on blocking oscillator for light up a LED using waste battery was carried out. -
Class D Audio Amplifier Basics
Application Note AN-1071 Class D Audio Amplifier Basics By Jun Honda & Jonathan Adams Table of Contents Page What is a Class D Audio Amplifier? – Theory of Operation..................2 Topology Comparison – Linear vs. Class D .........................................4 Analogy to a Synchronous Buck Converter..........................................5 Power Losses in the MOSFETs ...........................................................6 Half Bridge vs. Full Bridge....................................................................7 Major Cause of Imperfection ................................................................8 THD and Dead Time ............................................................................9 Audio Performance Measurement........................................................10 Shoot Through and Dead Time ............................................................11 Power Supply Pumping........................................................................12 EMI Consideration: Qrr in Body Diode .................................................13 Conclusion ...........................................................................................14 A Class D audio amplifier is basically a switching amplifier or PWM amplifier. There are a number of different classes of amplifiers. This application note takes a look at the definitions for the main classifications. www.irf.com AN-1071 1 AN-1071 What is a Class D Audio Amplifier - non-linearity of Class B designs is overcome, Theory of Operation without the inefficiencies -
Eimac Care and Feeding of Tubes Part 3
SECTION 3 ELECTRICAL DESIGN CONSIDERATIONS 3.1 CLASS OF OPERATION Most power grid tubes used in AF or RF amplifiers can be operated over a wide range of grid bias voltage (or in the case of grounded grid configuration, cathode bias voltage) as determined by specific performance requirements such as gain, linearity and efficiency. Changes in the bias voltage will vary the conduction angle (that being the portion of the 360° cycle of varying anode voltage during which anode current flows.) A useful system has been developed that identifies several common conditions of bias voltage (and resulting anode current conduction angle). The classifications thus assigned allow one to easily differentiate between the various operating conditions. Class A is generally considered to define a conduction angle of 360°, class B is a conduction angle of 180°, with class C less than 180° conduction angle. Class AB defines operation in the range between 180° and 360° of conduction. This class is further defined by using subscripts 1 and 2. Class AB1 has no grid current flow and class AB2 has some grid current flow during the anode conduction angle. Example Class AB2 operation - denotes an anode current conduction angle of 180° to 360° degrees and that grid current is flowing. The class of operation has nothing to do with whether a tube is grid- driven or cathode-driven. The magnitude of the grid bias voltage establishes the class of operation; the amount of drive voltage applied to the tube determines the actual conduction angle. The anode current conduction angle will determine to a great extent the overall anode efficiency. -
High-Frequency, High-Power Transistor Linear Power Amplifier Design
NPS ARCHIVE 1968 HUEBNER, R. HIGH-FREQUENCY, HIGH-POWER TRANSISTOR LINEAR POWER AMPLIFIER DESIGN by Ray Everett Huebner tIBRARY ^^ NAVAL POSTGRADUATE SCSwP,,. MONTEREY, CALIF.. 99040 UNITED STATES NAVAL POSTGRADUATE SCHOOL THESIS HIGH-FREQUENCY, HIGH-POWER TRANSISTOR LINEAR POWER AMPLIFIER DESIGN by Ray Everett Huebner September 1968 HIGH-FREQUENCY, HIGH-POWER TRANSISTOR LINEAR POWER AMPLIFIER DESIGN by Ray Everett Huebner Captain^ United States Marine Corps B,S,j Kansas State University, 1962 Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN ELECTRICAL ENGINEERING from the NAVAL POSTGRADUATE SCHOOL September 1968 ABSTRACT This thesis discusses in detail the physical and elec- trical characteristics of high-frequency, high-power trans- istors, and why class B amplifiers are necessary for linear power amplification of signals containing more than one frequency. Linear power amplifier design is contingent upon hav- ing a suitable design technique. "Suitable" often means being able to determine parameter values called for by that technique. Conjugate impedance matching is a suitable technique and three of the four parameter values can be accurately determined. In some cases manufacturers pro- vide data for this technique, titled "Large-signal parame- TABLE OF CONTENTS Section Page I Introduction 9 II High-Frequency, High-Power Transistors 12 1. Theoretical Limitations 12 2. Physical Design 18 The Overlay Transistor 19 The Interdigitated Transistor 24 3. Some Notes on Second Breakdown 26 4. Advancing the State-of-the-Art 29 5. Characterization for Power Amplifier 38 Purposes III Linear Power Amplifier Design . 43 1. General Aspects 43 2. Preliminary Design Discussion 55 3. -
CLASS 331 OSCILLATORS January 2011
CLASS 331 OSCILLATORS 331 - 1 331 OSCILLATORS 94.1 MOLECULAR OR PARTICLE RESONANT 34 .Particular frequency control TYPE (E.G., MASER) means 1 R AUTOMATIC FREQUENCY STABILIZATION 35 ..Electromechanical (e.g., motor) USING A PHASE OR FREQUENCY 36 R ..Reactance device (e.g., SENSING MEANS variable capacitors, saturable 2 .Plural oscillators controlled inductors, reactance tubes, 3 .Molecular resonance etc.) stabilization 36 C ...Capacitor controlled AFC 4 .Search sweep of oscillator 36 L ...Inductor controlled AFC 5 .Magnetron oscillator 1 A .AFC with logic elements 6 .Klystron oscillator 37 BEAT FREQUENCY 7 ..Plural controls 38 .Plural beating 8 .Transistorized controls 39 ..Single channel 9 .Oscillator with distributed 40 .Frequency or amplitude parameter-type discriminator adjustment or control 10 .Plural A.F.S. for a single 41 .Frequency stabilization oscillator 42 .With particular signal combining 11 ..Plural comparators or means (e.g., cavity mixer) discriminators 43 ..With filter in mixer output 12 ...With phase-shifted inputs circuit 13 ..Motor control of oscillator 44 WITH FREQUENCY CALIBRATION OR 14 .With intermittent comparison TESTING controls 45 POLYPHASE OUTPUT 15 .Amplitude compensation 46 PLURAL OSCILLATORS 16 .Tuning compensation 47 .Oscillator used to vary 17 .Particular error voltage control amplitude or frequency of (e.g., intergrating network) another oscillator 18 .With reference oscillator or 48 .Adjustable frequency source 49 .Selectively connected to common 19 ..Spectrum reference source output or oscillator substitution -
Sinusoidal and Non- Sinusoidal Oscillators
CHAPTER65 Learning Objectives ➣ What is an Oscillator? SINUSOIDAL ➣ Classification of Oscillators ➣ Damped and Undamped AND NON- Oscillations ➣ Oscillatory Circuit ➣ Essentials of a Feedback LC SINUSOIDAL Oscillator ➣ Tuned Base Oscillator ➣ Tuned Collector Oscillator OSCILLATORS ➣ Hartley Oscillator ➣ FET Hartley Oscillator ➣ Colpitts Oscillator ➣ Clapp Oscillator ➣ FET Colpitts Oscillator ➣ Crystal Controlled Oscillator ➣ Transistor Pierce Cystal Oscillator ➣ FET Pierce Oscillator ➣ Phase Shift Principle ➣ RC Phase Shift Oscillator ➣ Wien Bridge Oscillator ➣ Pulse Definitions ➣ Basic Requirements of a Sawtooth Generator ➣ UJT Sawtooth Generator ➣ Multivibrators (MV) ➣ Astable Multivibrator An oscillator is an electronic device used for ➣ Bistable Multivibrator (BMV) the purpose of generating a signal. Oscillators ➣ Schmitt Trigger are found in computers, wireless receivers ➣ Transistor Blocking Oscillator and transmitters, and audiofrequency equipment particularly music synthesizers 2408 Electrical Technology 65.1. What is an Oscillator ? An electronic oscillator may be defined in any one of the following four ways : 1. It is a circuit which converts dc energy into ac energy at a very high frequency; 2. It is an electronic source of alternating cur- rent or voltage having sine, square or sawtooth or pulse shapes; 3. It is a circuit which generates an ac output signal without requiring any externally ap- Oscillator plied input signal; 4. It is an unstable amplifier. These definitions exclude electromechanical alternators producing 50 Hz ac power or other devices which convert mechanical or heat energy into electric energy. 65.2. Comparison Between an Amplifier and an Oscillator As discussed in Chapter-10, an amplifier produces an output signal whose waveform is similar to the input signal but whose power level is generally high. -
AN593: Broadband Linear Power Amplifiers
Freescale Semiconductor, Inc. Order this document MOTOROLA by AN593/D 33333SEMICONDUCTOR APPLICATION NOTE AN593 BROADBAND LINEAR POWER AMPLIFIERS USING PUSH-PULL TRANSISTORS Prepared by: Helge Granberg RF Circuits Engineering INTRODUCTION These transistors are specified at 80 watts (PEP) output with intermodulation distortion products (IMD) rated at – 30 dB. Linear power amplifier operation, as used in SSB For broadband linear operation, a quiescent collector current transmitters, places stringent distortion requirements on the of 60 – 80 mA for each transistor should be provided. Higher high-power stages. To meet these distortion requirements N . quiescent current levels will reduce fifth order IMD products, . and to attain higher power levels than can be generally . but will have little effect on third order products except at achieved with a single transistor, a push-pull output O lower power levels. Generally, third order distortion is much c configuration is often employed. Although parallel operation more significant than the fifth order products. n can often meet the power output demands, the push-pull I A biasing adjustment is provided in the amplifier circuit mode offers improved even-harmonic suppression making , to compensate for variations in transistor current gain. This r it the better choice. The exact amount of even-harmonic adjustment allows control of the idling current for both the suppression available with push-pull stages is highly o output and driver devices. This control is also useful if the t dependent on several factors, the most significant one being amplifier is operated from a supply other than 28 volts. c the matching between the two output devices. -
Simple Blocking Oscillator for Waste Battery's Voltage Enhancement
International Journal of Information and Electronics Engineering, Vol. 6, No. 2, March 2016 Simple Blocking Oscillator for Waste Battery’s Voltage Enhancement Dewanto Harjunowibowo, Wiwit Widiawati, Anif Jamaluddin, and Furqon Idris zero. Since VBB<<VCC and does not affect the operation of Abstract—A system based on Blocking Oscillator (BO) has circuit therefore it can be neglected. been built and potentially produces high gain pulses voltage. This paper aims to discuss characteristic, work principle, and its potency of simple blocking oscillator to optimize batteries usage. The measurement of its peak to peak voltage (Vpp) and root means square voltage (Vrms) were conducted using digital oscilloscope and digital voltmeter. The experiment proves that the system produces high gain pulse electricity and driven LED without broke it out. The system could power a white LED 3.0-4.0 V using an input voltage of 0.98 VDC from waste battery. Using blocking oscillator, a battery may be used longer and more efficient until the battery energy almost ramps out to 0.5V. Index Terms—Blocking oscillator, characteristic, gain, led. Fig. 1. A triggered transistor blocking oscillator with base timing. Suppose a triggering signal is momentarily applied to the I. INTRODUCTION collector to lower its voltage. By transformer action, the base In order to increase battery life, some experiments has been will rise in potential. After VBE exceeds the cut in voltage, done, such as to design circuit building blocks with lower the transistor saturates and starts to draw current. The increase supply voltage and consuming sub-microwatt power. in collector current lowers the collector voltage, which in turn Reference [1] has built a circuit design which generates a DC raises the base voltage. -
The RFAL Technique for Cancellation of Distortion in Power Amplifiers
High Frequency Design From June 2004 High Frequency Electronics Copyright © 2004, Summit Technical Media, LLC DISTORTION REDUCTION The RFAL Technique for Cancellation of Distortion in Power Amplifiers By Romulo (Ray) Gutierrez Micronda LLC eflected signals This patented linearization have always been technique uses the infor- Rconsidered a curse mation present in the by circuit designers, FORWARD reflected input signal to wasting energy, reducing create a correction gain and adversely affect- OUTPUT signal that significantly ing system performance. REFLECTED reduces the distortion of This article describes a a power amplifier new technique that uses this normally trouble- some reflected signal to cancel output distor- tion, significantly increase linearity, and dou- ble the usable output power of single stage amplifiers. Figure 1 · A transistor’s nonlinear frequency spectrum. The RFAL Technique The basis for this technique is the behavior of a transistor amplifier operating under non- predistortion techniques. The RFAL can also linear conditions. At the input, the reflected improve the performance of feedforward sys- signal contains both the reflected input sig- tems when used in nested loop configuration. nals and the distortion products that are found at its output, as illustrated in Figure 1. Summary of the RFAL features: In the Reflect Forward Adaptive Linearizer • Efficient low intermodulation distortion (RFAL) amplifier, the forward signals and the configuration that doubles the output power reflected signals are sampled at the input of the Main Amplifier over wide input power using a directional coupler. These signals are and frequency ranges. then attenuated and phased properly before • Provides distortion cancellation up to the 1 combining them at a summing coupler. -
Generation of Broad-Band Chaos Using Blocking Oscillator Nikolai F
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS—I: FUNDAMENTAL THEORY APPLICATIONS, VOL. 48, NO. 6, JUNE 2001 673 Generation of Broad-Band Chaos Using Blocking Oscillator Nikolai F. Rulkov and Alexander R. Volkovskii Abstract—In this paper, we discuss fundamentals for the design of a source of chaotic signals based on a blocking oscillator circuit. We study a modification of a well-known circuit of blocking os- cillator which leads to the onset of chaotic oscillations. The output signal of such chaotic oscillator is a series of short term pulses char- acterized by chaotic fluctuations of time intervals between pulses. Such chaotic pulse signals posses a broad-band continuous power spectrum and short correlation length. We discuss the results of theoretical and experimental studies of nonlinear dynamics of the chaotic blocking oscillator. Index Terms—Bifurcations, chaos, nonlinear circuits. I. INTRODUCTION NTENSIVE studies of possible applications of chaotic sig- I nals are supported in part by the abilities of simple inex- pensive electrical circuits to generate complex chaotic signals. Quite a few simple autonomous nonlinear circuits that posses chaotic dynamics have been proposed and studied, see for ex- Fig. 1. Chaotic blocking oscillator circuit. ample [1]–[6]. Most of these nonlinear circuits produce chaotic signals in form of quasiharmonic oscillations. Chaos in such cir- stead of quasiharmonic chaotic signals are discussed in details cuits occurs through bifurcations from a regime of harmonic os- in [10], [12], [13]. cillation. The shape of the power spectrum of such chaotic sig- The core of the chaotic pulse oscillators is a circuit that gener- nals depends upon the amplitudes of higher harmonics which ates time intervals in accordance with the iterations of a chaotic occur due to nonlinear distortions of the original harmonic os- map.