Introduction to wave-generation and wave-shaping
File : 1.85 MB, 275 pages
Navy Electrical and Electronics Training Series – Modul 9
1. Tuned Circuits
2. Oscillators
3. Waveforms and Wave Generators
4. Wave Shaping
CONTENTS
INTRODUCTION TO TUNED CIRCUITS
When your radio or television set is turned on, many events take place within the “receiver” before you hear the sound or see the picture being sent by the transmitting station. Many different signals reach the antenna of a radio receiver at the same time. To select a station, the listener adjusts the tuning dial on the radio receiver until the desired station is heard. Within the radio or TV receiver, the actual “selecting” of the desired signal and the rejecting of the unwanted signals are accomplished by what is called a TUNED CIRCUIT. A tuned circuit consists of a coil and a capacitor connected in series or parallel. Later in this chapter you will see the application and advantages of both series- and parallel-tuned circuits. Whenever the characteristics of inductance and capacitance are found in a tuned circuit, the phenomenon as RESONANCE takes place.
You learned earlier in the Navy Electricity and Electronics Training Series, Module 2, chapter 4, that inductive reactance (XL) and capacitive reactance (XC) have opposite effects on circuit impedance (Z).
You also learned that if the frequency applied to an LCR circuit causes XL and XC to be equal, the circuit is RESONANT. If you realize that XL and XC can be equal ONLY at ONE FREQUENCY (the resonant frequency), then you will have learned the most important single fact about resonant circuits. This fact is the principle that enables tuned circuits in the radio receiver to select one particular frequency and reject all others. This is the reason why so much emphasis is placed on XL and X C in the discussions that follow…
INTRODUCTION TO OSCILATORS
WAVE GENERATORS play a prominent role in the field of electronics. They generate signals from a few hertz to several gigahertz (109 hertz). Modern wave generators use many different circuits and generate such outputs as SINUSOIDAL, SQUARE, RECTANGULAR, SAWTOOTH, and TRAPEZOIDAL waveshapes. These waveshapes serve many useful purposes in the electronic circuits you will be studying. For example, they are used extensively throughout the television receiver to reproduce both picture and sound.
One type of wave generator is known as an OSCILLATOR. An oscillator can be regarded as an amplifier which provides its own input signal. Oscillators are classified according to the waveshapes they produce and the requirements needed for them to produce oscillations.
WAVEFORMS
This chapter will present methods of generating waveforms. Before you begin to study how waveforms are generated, you need to know the basic characteristics of waveforms. This section will discuss basic periodic waveforms.
LIMITERS
As a technician, you will be confronted with many different types of LIMITING circuits. A LIMITER is defined as a device which limits some part of a waveform from exceeding a specified value.
Limiting circuits are used primarily for wave shaping and circuit-protection applications.
A limiter is little more than the half-wave rectifier you studied in NEETS, Module 6, Introduction to Electronic Emission, Tubes, and Power Supplies. By using a diode, a resistor, and sometimes a dc bias voltage, you can build a limiter that will eliminate the positive or negative alternations of an input waveform. Such a circuit can also limit a portion of the alternations to a specific voltage level. In this chapter you will be introduced to five types of limiters: SERIES-POSITIVE, SERIES-NEGATIVE, PARALLEL-POSITIVE, PARALLEL-NEGATIVE, and DUAL-DIODE LIMITERS. Both series- and parallel-positive and negative limiters use biasing to obtain certain wave shapes. They will be discussed in this chapter.
The diode in these circuits is the voltage-limiting component. Its polarity and location, with respect to ground, are the factors that determine circuit action. In series limiters, the diode is in series with the output. In parallel limiters, the diode is in parallel with the output.
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[...] 24 Modules : Module 1, Introduction to Matter, Energy, and Direct Current, introduces the course with a short history of electricity and electronics and proceeds into the characteristics of matter, energy, and direct current (dc). It also describes some of the general safety precautions and first-aid procedures that should be common knowledge for a person working in the field of electricity. Related safety hints are located throughout the rest of the series, as well. Module 2, Introduction to Alternating Current and Transformers, is an introduction to alternating current (ac) and transformers, including basic ac theory and fundamentals of electromagnetism, inductance, capacitance, impedance, and transformers. Module 3, Introduction to Circuit Protection, Control, and Measurement, encompasses circuit breakers, fuses, and current limiters used in circuit protection, as well as the theory and use of meters as electrical measuring devices. Module 4, Introduction to Electrical Conductors, Wiring Techniques, and Schematic Reading, presents conductor usage, insulation used as wire covering, splicing, termination of wiring, soldering, and reading electrical wiring diagrams. Module 5, Introduction to Generators and Motors, is an introduction to generators and motors, and covers the uses of ac and dc generators and motors in the conversion of electrical and mechanical energies. Module 6, Introduction to Electronic Emission, Tubes, and Power Supplies, ties the first five modules together in an introduction to vacuum tubes and vacuum-tube power supplies. Module 7, Introduction to Solid-State Devices and Power Supplies, is similar to module 6, but it is in reference to solid-state devices. Module 8, Introduction to Amplifiers, covers amplifiers. Module 9, Introduction to Wave-Generation and Wave-Shaping Circuits, discusses wave generation and wave-shaping circuits. Module 10, Introduction to Wave Propagation, Transmission Lines, and Antennas, presents the characteristics of wave propagation, transmission lines, and antennas. [...]
Good book a very useful, I have not seen the book like this before , very straight forward and FREEEEEEE, thanks a lot