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In metal music studies, “heaviness” has been acknowledged an essential element of the genre. Commonly associated with the distorted guitar, most work on heaviness has concentrated on the instrument’s sound. If respective research considered structural aspects of the guitar riff, then with a special focus on tempo, rhythm, tonality and form. This article analyses the interaction between distortion and harmonic structures on the electric guitar. Operationalising heaviness with a psychoacoustic model of sensory consonance, an acoustic experiment explores how guitar distortion affects acoustic features of harmonic structures. Since acoustic studies are limited in predicting perception, a listening test investigates distortion’s influence on listener perception. The findings indicate that both increasing distortion level and harmonic complexity reduce sensory consonance, especially when acting together. Acoustically, distortion shows a slightly stronger effect strength than structure; perceptually, the ratio is dependent on person-specific characteristics. Metalheads seem to be only little affected by sensory dissonance.

Probability and Statistics, Allan White and Hagbae Kim Electronic Hardware Reliability, Michael Pecht and Iuliana Bordelon Software Reliability, Carol Smidts Thermal Properties, David F. Besch Heat Management, Zbigniew J. Staszak Shielding and EMI Considerations, Don White Resistors and Resistive Materials, Jerry C. Whitaker Capacitance and Capacitors, Jerry C. Whitaker Inductors and Magnetic Properties, Jerry C. Whitaker Printed Wiring Boards, Ravindanath Kollipara and Vijai Tripathi Hybrid Microelectronics Technology, Jerry E. Sergent Surface Mount Technology, Glenn R. Blackwell Semiconductor Failure Modes, Jerry c. Whitaker Power System Protection Alternatives, Jerry C. Whitaker Facility Grounding, Jerry C. Whitaker Network Switching Concepts, Tsong-Ho Wu Network Communication, James E. Goldman Data Acquisition, Edward McConnell and Dave Jernigan Computer-Based Circuit Simulation, Bashir Al-Hashimi Audio Frequency Distortion Mechanisms and Analysis, Jerry C. Whitaker Video Display Distortion Mechanisms and Analysis, Jerry C. Whitaker Radio Frequency Distortion Mechanisms and Analysis, Samuel O. Agbo Digital Test Equipment and Measurement Systems, Jerry C. Whitaker Fourier Waveform Analysis, Jerry C. Hamann and John W. Pierre Computer Based Signal Analysis, Rodger E. Ziemer Systems Engineering Concepts, Gene DeSantis Disaster Planning and Recovery, Richard Rudman Safety and Protection Systems, Jerry C. Whitaker Conversion Tables, Jerry C. Whitaker Index

this paper presents the implementation in simulation of two control techniques for a drive system in electric motorcycle. The controls proposed are field-oriented control (FOC) and direct torque control (DTC). The analysis consists of comparing the two controls and analyze the advantages and disadvantages of each technique. The aim is validate the best technique that provides greater efficiency, easy of implement and most cost effective for a future implementation in a prototype electric motorcycle. The paper contributes to the implementation of means of transportation powered with electricity for student mobility in the city of Cuenca Ecuador and reducing of problems of environment pollution and traffic saturation.

The sound of the distorted electric guitar is particularly important for many metal music genres. It contributes to the music’s perception of heaviness, serves as a distinguishing marker, and is crucial for the power of productions. This article aims at extending the research on the distorted metal guitar and on metal music production by combining both fields of interest. By the means of isolated guitar tracks of original metal recordings, ten tracks in each of the last five decades served as sample for a historical analysis of metal guitar aesthetics including the aspects tuning, loudness, layering and spectral composition. Building upon this insight, an experimental analysis of 287 guitar recordings explored the effectiveness and effect of metal guitar production techniques. The article attempts to provide an empirical ground of the acoustics of metal guitar production in order to extend the still rare practice-based research and metal-oriented production manuals.

Nowadays, people pay more and more attention to logistics management. However, due to the global e-commerce supply chain information transfer is not timely; information distortion and system error, hundreds of billions of dollars every year have lost. In order to improve the efficiency of logistics management system and reduce the error rate, people put forward RFID logistics management system. At the same time, because the embedded technology has the advantages of flexibility, high integration and low price, the use of embedded technology to realize RFID becomes the mainstream. This paper, combining the two, designs a RFID logistics management system based on Nios II. The system consists of a Nios II embedded soft core, a FPGA, a LCD screen, a matrix keyboard etc. After test, it can read the information of goods in a certain range and show them on a LCD screen and users can use a keyboard to manage the warehouse. It also helps to improve the efficiency of logistics management and reduce the error rate.

A filterless class-AB/D audio power amplifier integrated into a feature-rich 2.5G/3G baseband processor in standard 65-nm CMOS technology is designed for direct battery hookup in mobile phone applications. Circuit techniques are used to overcome the voltage limitations of standard MOS transistors for operation at voltage levels of 2.5-4.8 V. Both amplifiers can drive more than 650 mW into an 8-? load with maximum distortion levels of 1% and 5% for class-D and class-AB, respectively, all from a 3.6-V power supply. The achieved power-supply-rejection ratios are 72 and 84 dB, respectively. The mono implementation of both amplifiers together is 0.44 mm2 .

This paper describes macromodeling of operational amplifiers for overdrive circuit design. Macromodels have been applied to operational amplifier simulations with good convergence. Also, macromodels allow the accurate simulation with not only double-power supply but also single-power supply. In this study, a macromodel has been applied to an overdrive circuit for sound effect design. Output waveform using the macromodel is compared with that using a pre-set model only with double-power supply and experiment. The output of the macromodel shows more accurate in amplitude, a frequency, and distortion than that of the pre-set model. From this result, the macromodel of the operational amplifier is suitable than the pre-set model in the overdrive circuit design.

This paper presents a highly power efficient 2/spl times/20-W class-D audio output power stage implemented in 0.6-/spl mu/m BCDMOS technology. The presented power stage is capable of driving 2/spl times/8-/spl Omega/ loads from a 20-V power supply at a power efficiency approaching 90%. Circuit details of thermal detection, over-current protection, and startup speaker click/pop are also presented. The performance of open-loop Class-D output stages are limited by the distortion mechanisms present within the power stage itself. A third-order PWM modulator was prototyped and used to dramatically improve the performance of the Class-D output stage by using feedback. The results of this work are also presented.

Audio mastering engineers have felt increasing pressure over the years to master recordings at ever increasing loudness levels as compared to other contemporary recordings, by way of dynamic compression, peak limiting, and hard clipping. This pursuit of loudness adds distortion, reduces fidelity and ultimately impairs audio quality. When radio stations play the already compromised audio from contemporary music through their typical FM processing chains, this confluence of degradation causes serious audio quality issues on air. Besides leading to listener fatigue, this can even be mistaken for poor reception by listeners, ultimately causing tune-out. When pre-distorted contemporary recordings are encoded through typical perceptual codecs, the codecs end up wasting bits trying to faithfully encode the distortion components, in lieu of the original audio. This paper shall examine what the music typically endures when broadcast on FM, and how that understanding led to the invention of the “undo” algorithm, which is applicable to both the broadcasting and recording industries, and automatically repairs some or most of the damage caused by these mastering techniques by adaptively de-clipping and de-compressing the mastered recordings.Insert abstract text.

The authors were very thorough in the intense study that they performed in this paper. The discusser was impressed with the amount of detail, research, and study that went into this paper. It pinpoints the need to study and design relative protection for people who happen to be in the wrong place at the wrong time. These comments are intended to offer suggestions for improvement and clarification of this paper. It is this discusser’s feeling that an abstract should be short and easy to read, in order to invite those with mild interest in the subject matter to read and study the rest of the paper. It appears to the discusser that such terms as ‘‘fenestrations vacated by fractured glazing’’ would be more clear and attractive to the reader if reduced to words like ‘‘broken windows’’ (Part of the discusser’s function in his practice as a Forensic Engineer is to report a technical cause of damage in such terminology that the nontechnician can understand it.) After a bit of confusion on the part of the discusser, it was realized that photos 3 and 4 had been transposed. After that, the explanations became understandable. In the same vein, it was realized that NW 5th Street was really a north-south dividing line, not an east-west dividing line. Also, the discusser was looking for some sort of data on eye-related injuries, but it was nowhere to be found. Finally, the discusser congratulates the authors for this study, which he hopes will work towards additional study to find safer fenestration materials and techniques.

Digital soundtracks have the capability of delivering lower distortion program signals with flat power bandwidth in the motion picture theater. Traditional two-way theater loudspeaker systems are presently being pushed far beyond their original performance limits with the new soundtracks, and three-way systems are now considered to be their future replacement. The authors have developed such systems for both small and large venues, and an installation of five new screen channels has been made in the Samuel Goldwyn Theater at the Academy of Motion Picture Arts and Sciences. System evolution, design, and performance will be discussed in detail in this paper.

International audience; Digital predistortion (DPD) is one of the most promising techniques for the linearization of power amplifiers. In this overview paper, some of the most important aspects related to this technique are briefly covered. State of the art on the DPD techniques, the associated signal processing algorithms and crest-factor reduction techniques are presented.

Rock and blues guitar players prefer the use of vacuum-tube amplifiers due to the harmonic structures developed when the amplifiers are overdriven. The disadvantages of vacuum tubes compared against solid-state implementations, such as power consumption, reliability, cost, etc., are far outweighed by the desirable sound characteristics of the overdriven vacuum-tube amplifier. There are many approaches to modeling vacuum-tube amplifier behaviors in solid-state implementations. These include a variety of both analog and digital techniques, some of which are judged to be good approximations to the tube sound. In this paper we present early results of experiments in using a neural network to model the distortion produced by an overdriven vacuum-tube amplifier. Our approach is to use artificial neural networks of the recurrent variety, specifically a Nonlinear AutoRegressive eXogenous (NARX) network, to capture the nonlinear, dynamic characteristics of vacuum-tube amplifiers. NARX networks of various sizes have been trained on data sets consisting of samples of both sinusoidal and raw electric guitar signals and the amplified output of those signals applied to a tube-based amplifier driven at various levels of saturation. Models are evaluated using both quantitative (e.g., RMS error) and qualitative (listening tests) assessment methods on data sets that were not used in the network training. Listening tests- considered by us to be the most important evaluation method-at this point in the work, are indicative of the potential for success in the modeling of a vacuum-tube amplifier using a recurrent neural network.

Uninterruptible Power Supply (UPS) is widely used in industry and electronics field in order to improve power quality. However, the distortion and interruption of output voltage will occur when UPS is applied to instantaneous impulsive load. This paper proposes a novel dynamic control strategy to resist impulsive load. When the impulsive load is imposed on UPS instantaneously, the impulsive current can be quickly sensed by the digital controller and the supplying power for the load is switched from inverter to bypass immediately. Therefore, the output voltage of UPS can be maintained uninterruptible. The proposed control strategy is verified by a 30 KVA UPS prototype.

The task of a power amplifier is to amplify a processed signal and deliver power into a load such as a loudspeaker. It should do this without introducing spurious signals, such as hum, noise, oscillation, or audible distortion, while driving a wide range of loads. Additionally, it should be tolerant of abuse, such as open or short circuits. Valves designed specifically for audio use generally have optimized configurations that are detailed in the manufacturer's data sheets. Designing output stages for audio valves from first principles is reinventing the wheel, but an overview of the practicalities is most useful; therefore, one will indulge in a brief analysis of a currently fashionable topology.

The main contain of this article specifically for audio directional system is hit by digital power amplifier, and to the rear for digital power amplifier stage full-bridge circuit simulation test. It proposes the question of the full-bridge circuit which you must pay attention to in the design process, and the article brings forward the method that improves specifically for these problems. The audio directional system works in the high frequency state, this audio directional system's operating frequency is 30khz, if you choose the transistor's switching speed is lower than the targeted audio system's operating frequency, then would it have the serious distortion. Therefore, the process of the selection of transistors must consider all aspects of the requirements. The switching valves according to pre-control strategy manages the opening sequence and turn-off, ultimately the AC power supply voltage transforms into DC power supply voltage. the multisim has the direct-viewing capture and the function of formidable simulation, it can easily change the simulation's parameters and access to a variety of visual simulation results. carrying on the comparison to the result of the simulation test, which has the nimble feasibility. It is the flexibility of using multisim, You can design a good circuit after carrying on pre-test in transformation effect and the higher harmonic to filter out aspects and so on.

Modern cellular phones incorporate hands-free operation, MP3 music playback and DMB reception. The users may wish to use these features for many hours and a low efficiency amplifier could deplete the battery in a short time. There are two classes of power amplifiers usually used for this application: Class-D and Class-AB. Class-D architectures provide the benefit of power efficiency at the cost of slightly reduced performance and a level of switching noise, which might, in some cases, interfere with RF functions such as mobile phone, GPS or FM radio reception. Class AB architecture has the benefit of higher audio quality and doesn't produce any switching noise, but its power efficiency is much lower. Notwithstanding their lower efficiency, the great majority of the headphone drivers in commerce operate in Class AB. A Class G is a high-efficiency analog amplifier without EMI problems that tries to bring together the best of Class AB and Class D. It uses multiple voltage rails and switches to the appropriate voltage as required by the instantaneous output voltage level. In this way, it never uses the high supply voltage when a low voltage output is required. The core of a Class G amplifier is the switching circuitry, which should enable a smooth handover of the load driving between the low voltage supply and the higher one. Furthermore, the switching strategy should satisfy two key points: first, the distortion due to the switching operation must be minimized to maintain high audio quality; second, the switching point must be as close as possible to the low voltage supply to maximize efficiency.

A 10-b 20-Msample/s analog-to-digital converter fabricated in a 0.9- mu m CMOS technology is described. The converter uses a pipelined nine-stage architecture with fully differential analog circuits and achieves a signal-to-noise-and-distortion ratio (SNDR) of 60 dB with a full-scale sinusoidal input at 5 MHz. It occupies a 8.7 mm/sup 2/ and dissipates 240 mW. >

A 16-Ω earpiece driver design with a built-in volume control for use in mobile phones or other portable devices is described. The fabrication was done with UMC 65-nm CMOS technology. The dual channel design features −91 dB THD at 2.5 V pp , 1 kHz and 94 dB SNR in measurement while consuming 7.6 mW and 0.1 mm2 per channel.

A 10GSamples/second (GS/s) 5-b flash analog-todigital converter (ADC) that includes a feedthrough cancellation track and hold amplifier (THA) is presented. The proposed 10GS/s switched source follower (SSF) THA removes the input feedthrough error during the hold mode, which dramatically improves the settling behavior than previous designs. The proposed track and hold circuit achieves a total harmonic distortion (THD) of −37.3dBc at 10GS/s and an input frequency of 4GHz, which is 4.5dBc lower than the THD of traditional SSF THAs. The THA core only consumes 26mW and this is the minimum power consumption of THA above 10GS/s ever reported. In addition, a proposed comparator array to address the overdrive recovery issue is implemented for very high speed ADC. A reference ladder with source followers is applied to reduce the pre-amplifier feedthrough distortion by 10 times. This design is implemented in IBM 65nm CMOS technology with 1.4V power supply, 1.2V peak-to-peak differential input amplitude, and 1V peak-to-peak clock swing.

The linear amplifiers that are currently used in ADSL line-drivers have a very low efficiency, due to the high peak-to-average voltage ratio of the ADSL signals, and the low performance of those amplifiers at low signal amplitudes. Despite the larger distortion of the output signal, switching amplifiers are a promising alternative, since their efficiency could theoretically attain 100%. This paper presents a new level-shifter for the n-type high side switch of the output stage of a high-voltage switching amplifier.

A half-rate source-series terminated TX, operating at data-rates up to 16Gb/s, targets chip-to-chip on-board interconnects. The TX features a 4-tap FFE, tunable termination, and clock-cleanup circuitry for low duty-cycle distortion, and is capable of driving loads referenced to a variable termination voltage, including Gnd, VDD, and VDD/2. Implemented in 65nm SOI, it occupies an area of 230 times 56mum2 and draws 57.5mA from a 1V supply at 16Gb/s.

To address the demand for miniaturization and low cost in a cellphone, we aimed to eliminate the isolator and DC-DC converter. We propose a novel switch-type power amplifier (PA) using a strong junction PHEMT (JPHEMT) PA instead of HBT from the point of view of the performance under load-impedance variation. In high output power mode, the performance of this PA is the same as that of the conventional PA. In low output power mode, it operates as a single-stage PA and satisfies distortion characteristics without causing deterioration of efficiency.

In this paper, we present high drain efficiency of 34% and wide-band characteristics of single-ended 200W GaN HEMT power amplifier for 2.1 GHz W-CDMA application. We also confirmed that GaN HEMT power amplifier has low memory effect and adjacent channel leakage power ratio (A.C.L.R.) is sufficiently reduced for the application by utilizing digital predistortion (D.P.D.) system.

This chapter gives an overview on the way amplifier design has evolved in the past three or four decades. Designs using germanium devices appeared first, but suffered severely. Proper complementary power devices appeared in the late 1960s, and full complementary output stages soon proved to give less distortion than their quasi-complementary predecessors from the vulnerability of germanium to even moderately high temperatures. The vast majority of audio amplifiers use the conventional architecture, which is shown in the chapter. There are three stages of the architecture: a transconductance stage (differential voltage in, current out), a transimpedance stage (current in, voltage out), and a unity-voltage gain output stage. The chapter elaborates on these three stages of architecture. A two-stage amplifier is likely to be more complex in its gain structure than a three-stage amplifier. The chapter also discusses the power amplifier classes. All power amplifiers are either AC-coupled or DC-coupled. There is a huge body of knowledge devoted to the art of keeping feedback loops stable while optimizing their accuracy, which is called Control Theory. Technical bookshop yields some intimidatingly fat volumes like ‘Control System Design.’

People are often motivated to be entertaining. Past work has shown that those given entertainment goals tell stories differently than those given accuracy goals (e.g. Dudukovic, Marsh, & Tversky, 2004). In three studies we investigate the influence of the motive to entertain on story distortion. In each study, we found that the motive to entertain was related to story distortion. For instance, participants who opened a cockroach-infested container of food exaggerated the size of cockroaches when describing the event to a confederate, and participants telling a group of peers about the first time they got drunk claimed to have been more drunk than when they told the same story to a tape recorder. Furthermore, it was also the case the distorting influence of the motive to tell a good story occasionally occurred without awareness, influencing not only their descriptions of the events but their memories of them as well.

A digital input controller for audio class-D amplifiers is presented. The controller utilizes specially configured integrated DAC and power stage feedback loop to suppress distortion components coming from power-stage switching with digital input capability. The class-D amplifier system with the controller and an existing power stage achieves 113dB DR, 0.0018% THD+N with 10W output power, and 0.004% THD+N with 100W output power into 4Omega load

This paper describes a new low-power write driver circuit for mobile hard disk drive preamplifiers. To achieve low power consumption, we developed a write driver circuit with a single-stage MOS transistor as the current driver, which both switches and controls the write current. We also developed a reflection cancellation method to suppress the distortion of the write current waveform during write transition. Fabricated by 0.35-/spl mu/m SOI-BiCMOS technology, this write driver circuit dissipates low power, 380 mW (at 100 MHz).

Microphones are called as a general class transducers , changing acoustical energy, sound, into electrical energy, voltage. They typically put out much lower voltage levels than most audio gear, so they must be amplified by a microphone preamplifier to get to usable levels. A typical amount of voltage delivered by a professional microphone is 13 mV (0.013 V), a rather small voltage, for 94 dB SPL, 1 a rather loud level. Thus, microphones must be connected to microphone inputs, and the converse is true too: line-level devices like CD players must be connected to line-level inputs. If a line-level device is connected to a microphone input, the result will typically be overload or bad distortion. If a microphone is connected to a line-level input and the gain is raised high to hear it at all, the result will typically be noisy or hissy. This is complicated by the microphone attenuate (MIC ATT) switch on some cameras that allows high-level microphone outputs (when encountering loud sound) to be accommodated by low-level (sensitive) microphone inputs.

Publisher Summary This chapter discusses about the ADC analog inputs and the various methods available for achieving optimum performance. The ADC driver (DAC buffer) selection criteria and the amplifier DC and AC performance considerations are presented. Popular converter dynamic performance specifications and the key DC and AC Op Amp specifications for ADC/DAC applications are illustrated. Rail-rail input stages and the output stages are explored. It also delves into gain and level-shifting circuits using Op Amps and the characteristics of AD77xx family of ADCs are illustrated. Low voltage single-supply ADCs, such as the AD746x, are best driven directly from low impedance sources. If drive amplifier is required, it must operate on a higher supply voltage to utilize the full input range of the ADC. Driving single-supply ADCs with scaled inputs and driving differential input CMOS switched capacitor ADCs are discussed. It examines a few simple single-ended drive circuits suitable for CMOS ADCs. A fully differential ADC design offers the advantages of good common-mode rejection, reduction in second order distortion products, and simplified factory trimming algorithms. A fully differential driver usually optimizes overall performance. The chapter looks into driving ADCs with differential amplifiers. The two types of differential op amp drivers—the first based on utilizing dual op amps, and the second which utilizes fully integrated differential amplifiers—are discussed. The last part examines driving differential input ADCs with integrated differential drivers

Conventional fully differential HF CMOS operational amplifiers (op amps) use an extra circuit to perform common-mode feedback (CMFB), which results in signal distortion and/or asymmetry as the signal swing increases. To solve this problem, two fully differential CMOS op amps that are based on merging two single-ended-output op amps are proposed and analyzed. Through the inherent differential-to-single-ended conversion circuitry, CMFB can be efficiently performed without extra circuits. The output signals are not distorted, and the HF performance is not degraded. Simulation and experimental results have confirmed the performance of the proposed new op amps. >

A sub-sampling IF digitizer that uses a passive sampling mixer to improve distortion and a BiCMOS comparator to improve the SNR of a passive loop-filter based /spl Sigma//spl Delta/ converter is described. Volterra series analysis allows accurate prediction of distortion in the sampling mixer. A bipolar emitter-coupled pair based preamplifier in the comparator helps to relax overdrive recovery requirements of the regenerative latch and improve the speed of the comparator.

The design of a real-time system that measures and monitors the fundamental parameters of an uninterruptible power supply (UPS) in which it is incorporated is described. The system is based on a microcontroller (MCS-96 family) with a built-in 10-bit A/D converter. The parameters being measured in real-time are the amplitude, the frequency and the distortion of the UPS output AC signal. The charging state of the battery cells, the supply current of the battery and the signal level at specific test points on the UPS circuit board are also measured and monitored. These parameters are used in the real-time calculation of the remaining time before the UPS battery is exhausted and, in case of malfunction, the fault is located and the UPS is safely turned off.

Publisher Summary This chapter describes and contextualizes the Sound Gallery and the ideas that inform it. A working prototype of the Sound Gallery system was developed at the University of Sussex during the summer of 1999. The Sound Gallery is an ongoing experiment in art and science that grew out of research in the field of evolutionary electronics at the University of Sussex, England. The aim of this experiment is to utilize ideas and techniques derived from the science of artificial life (A-Life) to create an interactive and adaptive installation artwork that displays aesthetically interesting behavior. The field of A-Life is one that has been explored by a number of recent artists. It has spawned a diversity of new media and has proven a rich source of inspiration. There now exists a substantial body of work belonging to the canon of A-Life art, and a growing number of artist/scientists who are increasingly active in the field. The sound gallery adds a new artwork to this lineage, drawing inspiration from other works of A-Life art, but also making some notable advances. The aim of the sound gallery is to take this statement literally, and to its logical extreme: A sound source is transformed into “music” through repetition and distortion as it plays through four separate speakers simultaneously. The signal to each speaker is endowed with variations by the intervention of separate signal-processing circuits. The electronic character and makeup of these circuits, and hence the precise distortion effects they entail, are perpetually in a state of flux and change. The circuits are constantly manipulated and reconfigured through a process of artificial evolution driven by aesthetic selection pressures. The four speakers are to be positioned in an open gallery setting. Audience members, passersby, and curious parties will be encouraged to interact with this gallery space in whatever ways they feel fit. Sensors in the gallery will track the movements of those present over time.

Conference Name:International Conference on Sensors and Control Techniques (ICSC 2000). Conference Address: WUHAN, PEOPLES R CHINA. Time:JUN 19-21, 2000.

For original paper see C. Chan, H. Ling and O. Choy, ibid., vol.30, no.9, pp.1018-19 (1995). The goal of the original paper was to develop a novel FM demodulator based on a Gilbert multiplier that can operate with a single 1.2 V battery. In this Comment the author suggests that the original paper contained some errors and that the cell developed was not at all novel and is actually very well known. A reply by the original authors is included.

Advances in cost effective consumer I. C. technology have made it attractive to redesign the chroma system consolidating all active circuit functions into a single chip. The design goals for the new system were: 1) It must retrofit into the system. (No new modules other than the chroma module itself can be generated.) 2) Parts count must be minimized. 3) Adjustments must be minimized. 4) The amount of printed circuit board area utilized must be minimized. 5) The new system should have a flesh tone correction system that does not distort greens or blues, and minimizes distortion in the yellow region while providing effective flesh tone correction. 6) The chip should be adaptable to either color difference or RGB systems. 7) The chip should have a large, stable output swing capability to simplify the requirements placed on the video output stages. 8) Performance should equal or exceed the present two chip system in every area. 9) A significant cost savings must result.

FOR many years, the use of rectifier motive power was considered impracticable for several reasons, one of which involved the telephone interference problem. Corrective measures considered necessary to minimize power supply wave distortion of the single-phase rectifier to a degree which would be satisfactory for telephone communication rendered this type of motive power unacceptable to locomotive builders and to railroads.

It is generally recognized that if overload can be prevented, reverse-bias (gain decreases as emitter current decreases) in gain-controlled transistorized video IF amplifiers is preferred because of the superior bandpass stability throughout the AGC range and because of the uniformity in AGC tracking. Evaluation of overload distortion as a function of gain-control and source impedance indicates what signal levels can be tolerated at various operating conditions. Design based on overload evaluation has resulted in four-stage, 45 MHz amplifiers for color receivers having 70 db power gain, 60 db gain reduction capability, signal handling capability of 400 millivolts at the IF input of 50 ohms, and linear output capability of 3. 5 volts of video at 2900 ohms.

The high-speed duplication of previously recorded magnetic tapes has made the tape radio network practical. For example, each of the two major radio networks in Mexico duplicates over 19,000 seven-inch reels of taped programs per month for their several hundred affiliated stations. Since the tapes are erasable and wire program circuits are seldom used, these networks operate very economically, and the quality of their recorded programs is unimpaired by losses in transmission. Likewise, the adoption of Automatic Programming Systems for radio broadcasting will create a demand for syndicated magnetic tape programs and tape libraries. High-speed magnetic tape duplicators are also utilized for the mass production of tape recordings for entertainment, education, churches, libraries for the blind, reviews of professional publications, and sales information for large field sales organizations. The Ampex Model S-3200 tape duplicator with ten slaves will produce up to ten copies at one time of 15, 7\frac{1}{2} , or 3\frac{3}{4} ips master recordings at 60 ips. The copies can be recorded to be reproduced either at the speed of the master or at half speed; i.e., 3\frac{3}{4} ips copies from a 7\frac{1}{2} ips master. The duplicates may be either half-track, double-track, full-track, or two-track stereophonic. Comparisons are made of the degradation of the signal-to-noise ratio, frequency response, and distortion with respect to the number of generations of the duplicates. With optimum adjustment of the equipment, it is very difficult to identify the fourth generation copy from the master recording.

As part of an industry study by an Ad Hoc Committee for the Joint Committee for Intersociety Coordination into color TV transmission and reception problems resulting in color differences, a subcommittee, under the auspices of the National Association of Broadcasters, made a study of the possible contributing effect being made by the use of Color Video Processing Amplifiers. The committee study indicates that four or more color video processing amplifiers may be used between the point of origination and the TV transmitter. Cumulative errors in two or more processing amplifiers in cascade can result in signal distortion. Minimized use of color processing amplifiers appears to be in order and is recommended by the committee.

The paper deals with popularizing hi-fi listening facilities in Europe which, due to a difference in broadcasting practice is easier over there than in the United States. These differences are analyzed and the conclusion of the writer is that a large contingent of hi-fi listeners in Europe could be created by improving the reproduction quality of fm radio sets without increasing the cost too much. As a distortion limit for this purpose a figure of 1 per cent is chosen, while the output power should be near the 10-watt figure. To realize these properties a special circuit has been designed viz., a single-ended push-pull output stage with combined positive and negative feedback. A loudspeaker with a voice coil impedance of 800 ohms is being used, making an output transformer superfluous. This direct coupling is one of the necessities to get a cheap but very good setup. Further, the so-called 3D system and means for getting rid of the keyhole effect are discussed.

Compact disk (CD) players have strengthened what was formerly one of the weakest links of audio systems-the mechanical conversion of recorded sound into electric signals. They have almost none of the distortion produced by turntables and vinyl records. Digital information, in the form of small pits, is inscribed onto plastic disks and detected by laser. However, another weak link in audio systems-the conversion of electric signals to sound-remains weak, as advances in speaker technology have been slow, and even the best speakers are highly sensitive to placement. The objections that have been raised to the sound produced by CD players are discussed. It is pointed out that in view of the wide selection of available recordings for turntables, and the large capital investment that many consumers have made in record collections over the years, turntables seem destined to remain in many homes for some time. Some of the electronic synthesizers that are now available for home use are described.

A telephone channel simulator has been implemented on the Lincoln Digital Voice Terminal (LDVT). This technical note first reviews the various distortions that occur in telephone channels and then describes the implementation. The results obtained indicate that the potential of the LDVT goes beyond the original intent of its use as a speech digitizer.

This magnetic recording issue of Transactions brings to mind some historical "audio plans" for magnetic recorders. In its first fifty years magnetic recording never was a serious rival to the disk phonograph for prerecorded music. But fifteen years ago magnetic recording seemed unique in its ability to provide uninterrupted, long playing, high quality sound, as compared to 78-rpm disks which had to be changed every five minutes. Magnetic recording is no longer unique for long playing nor for stereo. Does it have any exclusive features left? There are quite a few. Tape recording has the reputation for superior fidelity, which is retained throughout a practically unlimited life. Tape furnishes three or more channels for enhanced stereo, and even with two channels it gives better separation and lower distortion than disks. Tape cartridges are rugged, in contrast to delicate disk surfaces. They are more compact, easier to store, and easier to use. A cartridge changer gives many hours of unattended programming. The erase feature allows interesting possibilities for the sale of music, separately from the cartridge, by vending machines where one could insert an unrecorded cartridge and select the music to be recorded. An important problem has been cost. In the next few years recorded tape music may be commonplace. Let us hope that it will bring uncommonly excellent audio quality.

This paper describes and explains the theory of the Feed-back principle and demonstrates how stability of amplification, reduction of modulation products, and certain other advantages follow when stabilized feed-back is applied to an amplifier. The underlying principle of design by means of which ``singing'' is avoided also is set Forth. The paper concludes with some examples of results obtained on amplifiers which have been built employing this new principle.