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Inhaltsverzeichnis

Frontmatter

1. Signal Processing

Abstract
This first chapter concentrates on the processing of voltages and currents in circuits or networks formed from combinations of the three fundamental circuit components, the resistor, capacitor and inductor. The relationship between the currents and voltages will be discussed for active circuits, and will serve as an introduction to network or circuit analysis in chapter 2.
Graham Bishop

2. Network Analysis

Abstract
Having dealt in chapter 1 with simple R-L-C circuits and obtained their frequency responses and characteristics to step and sinusoidal signals, more complex networks supplied with more complex signals are now analysed, using the various circuit theorems available to simplify the analysis.
Graham Bishop

3. Transistors and their Use in Linear Circuits

Abstract
The transistor is the basic amplifying device incorporated in operational amplifier designs, in particular integrated circuits. External circuitry applied to an amplifier composed of one or more transistors can be made to transform the amplifier into a function generator, as seen in later chapters. This chapter describes the construction and operation of semiconductor devices and in particular the transistor in its many forms. The basic transistor amplifier is then constructed, this being a fundamental component of the more sophisticated operational amplifier.
Graham Bishop

4. Amplification

Abstract
Gain is synonymous with amplification and is defined as the ratio of output to input quantities, not the difference between the output and input quantities. Three forms of gain are commonly used in technical work, these being power gain, voltage gain and current gain, the first being the multiple of the other two. Hence
$$power\;gain=\left( {voltage\;gain} \right)\times \left( {current\;gain} \right)$$
Graham Bishop

5. Feedback

Abstract
Feedback occurs in one form or another in every amplifier and can take the form of desired feedback where the response can be intentionally altered or undesired feedback such as that owing to stray capacitance as mentioned in chapter 1. Undesired feedback can be minimised with correction circuitry or intentional feedback in the form of connection between the output and input via one of many coupling circuits. The amplifier described in section 3.6 contains no intentional feedback and incorporates many undesirable features such as noise, distortion, nonlinearity and mismatch of impedances. The circuit of section 3.9, however, incorporates negative feedback which reduces the effect of these inherent faults. A further form of feedback exists, positive feedback, which again can be inadvertant and give rise to unwanted oscillations or can be intentional to cause an amplifier to oscillate under controlled conditions. This chapter outlines the basic principles of negative and positive feedback and serves as an introduction to the operational amplifier of chapters 6 and 7 where one or both forms of feedback are always incorporated in the circuit design.
Graham Bishop

6. The Operational Amplifier

Abstract
A voltage-derived shunt feedback amplifier as outlined in section 5.3 is used as the operational amplifier since the amplifier parameters are least disturbed by the feedback components with this mode of connection. The gain of the operational amplifier is −Z f/Z s and a variety of applications exist with suitable components substituted for Z f and Z s, which are described in chapter 7. The design and construction of the operational amplifier is described in this chapter associated with both the discrete component and integrated circuit types.
Graham Bishop

7. Basic Operational Amplifier Functions

Abstract
The operational amplifier is basically a differential amplifier with two inputs, one inverting and the other non-inverting. Any signal applied to the inverting input will appear at the output in an amplified inverted form. Similarly, any signal applied to the non-inverting input will appear at the output as an amplified form of the input. Signals applied to both inputs will add or subtract accordingly at the output giving true differential amplification. Identical inputs to both input terminals should, if correctly set up, produce zero output. Figure 7.1 illustrates this simple application of the operational amplifier using d.c. and a.c. signals which are applied as V 1 and V 2 to produce V OUT. The remainder of this chapter demonstrates many other simple applications of the basic operational amplifier as a prelude to the working circuits of chapter 8.
Graham Bishop

8. Operational Amplifier Applications

Abstract
In this chapter a selection of practical circuits is given to coordinate the theory and circuitry of the preceding chapters and to enable the characteristics and functions of the linear circuits to be demonstrated with a minimum of experimentation with component values. The circuits are designed around the 741 operational amplifier described in chapter 6, although a variety of other operational amplifiers will perform in a similar way to the 741 and can be substituted in the circuits.* The 741 requires a supply voltage of ±3–18 V, offset adjustment being optional in all circuits and being achieved by connection of a 1 kΩ potentiometer between pins 1 and 5, the slider going to −VCC. Component values are not critical and in most cases 10 per cent values are suitable. The circuits are divided into seven sections from simple amplification to pulse-coded modulators, and combinations of these circuits are possible for more complex function generators.
Graham Bishop

9. Digitalisation of Analogue Signals

Abstract
The introduction of low-priced digital integrated circuits and extensive range of MOS signal processing devices and the advantages of digital processing as opposed to analogue processing have prompted electronics design engineers to use digitalisation techniques in many applications previously dominated by the ‘741’ technology. For many applications combinations of analogue and digital are used, often on one integrated circuit chip. The processes described in the previous chapters are, however, still adopted, such as the amplification and feedback principles; much of the processing is, however, in digital form.
Graham Bishop

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