# RAE 7650 objectives and syllabus

## 3 Electronic principles and practice

### Examination objectives

3.1 For d.c. circuits

3.1.1 state Ohm's law equation and use it to solve simple problems

3.1.2 calculate total voltage and current in series and parallel circuits

3.1.3 calculate power in a d.c. circuit

3.1.4 calculate the effective resistance of resistors in series and parallel.

3.2 For a.c. circuits

3.2.1 state the terms which define the sine wave

3.2.2 calculate the effective capacitance in series and parallel circuits

3.2.3 calculate the effective inductance in series circuits

3.2.4 explain what is meant by inductive reactance, capacitive reactance and impedance

3.2.5 explain the effects of inductive reactance, capacitive reactance and impedance

3.2.6 solve simple problems.

3.3 For tuned circuits

3.3.1 state the characteristics and calculate the resonant frequency of series and parallel tuned circuits

3.3.2 explain the magnification of current or voltage at resonance.

3.4 Explain how a transformer functions and describe its uses.

3.5 Explain the use of the decibel to express ratios and levels of power and voltage.

3.6 Explain in simple terms

3.6.1 the operation of the junction diode and its use as a rectifier, voltage regulator and variable capacitor

3.6.2 operation of npn and pnp transistors and their uses in the three common configurations, emphasizing biasing and input and output impedance

3.6.3 the field effect transistor: how its characteristics differ from npn and pnp transistors

3.6.4 the integrated circuit.

3.7 Explain the use of the transistor as a switch.

3.8 Describe the application of solid state devices in receivers and transmitters.

3.9 Describe the principles of operation of typical power supplies for solid state equipment.

### Syllabus

3.1

3.1.1 The meaning of basic electrical terms; voltage, current, resistance, conductor, and insulator.

3.1.2 The relationship between voltage, current, resistance and power in a d.c. circuit.

3.2

3.2.1 The sine wave, definition of amplitude, frequency and period; peak, peak-to- peak, instantaneous, average and r.m.s. values. Simple explanation of the terms: phase angle, phase difference, phase lag and lead.

3.2.2 Inductance and capacitance; units, inductive and capacitive reactance. Reactance impedance and power in an a.c. circuit.

3.3 Series and parallel tuned circuits, resonance, impedance, dynamic resistance, calculation of resonant frequency; amplification of current or voltage at resonance; Q (magnification) factor.

3.4 Function and uses of the transformer.

3.5 Simple explanation of how the decibel notation is used to express ratios of power and voltage and how it may also be used to define power levels.

3.6 Characteristics of junction diodes, npn, pnp and field effect transistors.

3.7 The common transistor circuit configurations, emphasizing the biasing arrangements and conditions, and input and output impedances.

3.8 Use of solid state devices as

3.8.1 audio and radio frequency amplifiers

3.8.2 oscillators

3.8.3 mixers

3.8.4 demodulators

3.8.5 switches.

3.9 Rectification, smoothing and voltage stabilization arrangements in low voltage supplies.

## 4 Receivers, transmitters and transceivers

### Examination objectives

4.1 For superheterodyne receivers, explain

4.1.1 the principle of operation

4.1.2 choice of intermediate frequencies; adjacent channel and image frequency (second channel interference)

4.1.3 demodulation, reception of Morse and telephony (s.s.b. and f.m.)

4.1.4 simple automatic gain control (a.g.c.).

4.2 For transmitters, explain

4.2.1 oscillators and the factors affecting their stability

4.2.2 the function of oscillators, mixers, power amplifiers

4.2.3 modulation and types of emission (s.s.b. and f.m.)

4.2.4 the use of a valve as a power amplifier.

4.3 Explain the procedure for the adjustment and tuning of transceivers, including the use of dummy load.

### Syllabus

4.1

4.1.1 The superheterodyne principle of reception. Principles of reception of Morse and telephony (s.s.b. and f.m.) in terms of radio frequency amplification; frequency changing; demodulation or detection; audio amplification.

4.1.2 Advantages and disadvantages of high and low intermediate frequencies; adjacent channel and image frequency (second channel) interference and their avoidance.

4.1.3 Typical receivers; use of beat frequency oscillator. Characteristics of a single sideband signal and the purpose of a carrier insertion oscillator. Characteristics of an f.m. signal and the purpose of a ratio detector.

4.1.4 Reasons for automatic gain control; explanation of simple r.f. derived system.

4.2

4.2.1 Oscillators; stability of variable frequency and crystal controlled oscillators; factors affecting stability. Synthesizers, advantages and disadvantages: purpose of each stage with block diagram.

4.2.2 Transmitter stages; function of mixers, high and low power amplifiers (including linear types). Automatic level control (a.l.c.).

4.2.3 Methods of modulation and types of emission (s.s.b. and f.m.). Adjustment of modulation level. Relative advantages of Morse and telephony (s.s.b. and f.m.).

4.2.4 Valves, their application as r.f. power amplifiers; advantages and disadvantages.

4.3 Transceivers, block diagram; tuning and adjustment of controls. Use of dummy load.

## 5 Transmitter interference

### Examination objectives

5.1 Describe the consequences of poor frequency stability.

5.2 For spurious emissions

5.2.1 describe their causes

5.2.2 describe methods, appropriate to the Amateur Service, of detecting and recognizing their presence

5.2.3 describe, in practical terms, the measures which should be taken in the design, construction and operation of transmitters and the use of filters to minimize them.

5.3 Demonstrate knowledge of frequency checking equipment.

### Syllabus

5 1 Frequency stability; consequences of poor stability; risks of interference, out-of-band radiation.

5.2 Spurious emissions, causes and methods of prevention: harmonics of the radiated frequency, direct radiation from frequency determining stages (including synthesizers) and mixer stages of a transmitter, parasitic oscillations, excessive sidebands due to over modulation. Excessive deviation of f.m. transmitters (voice and data communications). Frequency synthesizers; problems of interference if out of lock.

5.3 Frequency checking.

(Reproduced by kind permission of The City & Guilds of London Institute)

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