COM4LAB: RxTx 1 - Components and AM, FM, PSK

The COM4LAB courses in transmission and reception technology explain the structure of classic and modern radio systems and the modulation of signals step by step. The properties of the signals are analysed in more detail in the time and frequency domains. For this purpose, there is a transmitter and a receiver system on the board in which all components can be analysed individually.

This course "Analogue Transmission Techniques AM, FM and PSK" covers the superheterodyne architecture and the basic analogue modulations AM, FM and PSK.

Total duration: Up to 16 hours

Target audience

Among others, the course can be used to support the training process for the following professions:

• electronics technician for devices and systems
• electronics technician for information and system technology
• aircraft electronics technician
• system electronics technician 

Learning objectives

The students are to:

• be able to identify all components of a transmitter and receiver system,
• learn how signals are measured in the baseband, in the intermediate frequency and in the high frequency range,
• experience which influences affect the quality of a radio link and how these can be recognised,
• practise the practical handling of analogue modulations (AM, FM, PSK) and analyse them.

Topics

The course covers the following topics:

• How mixers work in communications engineering (local oscillator-mixer-filter structures),
• Characteristics of single-side and double-sideband signals, high-side and low-side mixers, etc.,
• The function of amplifiers and filters,
• Functionality of a spectrum analyser (sweep mode),
• Comparison and analysis of modulations, such as amplitude modulation, frequency modulation, phase modulation,
• Transmission of analogue audio signals and digital signals,
• Recovery of the carrier frequency.

Previous knowledge

• Students need knowledge of the structure of electronic circuits in order to successfully complete the course.
• The use of formulae is a prerequisite. It is important to be able to work with complex numbers in Cartesian form and in polar coordinates in order to interpret constellation diagrams.
• Students must be familiar with the basics of communications engineering. The meaning of the terms phase, amplitude and frequency is assumed.
• The difference between the frequency domain and the time domain of a signal is important, although the range of a Fourier transformation is not necessary.
• Knowledge of exponential and logarithmic laws is an advantage when converting power between watts and dBm.