Abstract:

The paper describes the use of concept maps for the presentation of signal transmission techniques that is digitization, modulation and multiplexing. The basic aim is for the students to develop a grasp of the various types of modulation as well as of how modulation methods are associated with transmission techniques such as digitization and multiplexing. The relevant lecture is a 2-hour one and is implemented in the context of the 5th-semester “Telecommunication Systems” course offered at the Dept. of Electrical & Electronic Engineering Educators, School of Pedagogical & Technological Education (ASPETE), Athens, Greece.

Concept maps are used to present the following signal transmission techniques (including their possible interrelations):
- Digitization techniques such as pulse-code modulation (PCM) and δ-modulation.
- Analog modulation techniques such as amplitude, frequency and phase modulation (AM, FM and PM, respectively).
- Digital (shift-keying) modulation techniques such as amplitude, frequency and phase shift-keying (ASK, FSK, PSK, respectively).
- Modulation techniques on a pulse carrier such as pulse-amplitude, pulse-duration and pulse-position modulation (PAM, PDM and PPM, respectively).
- Multiplexing techniques such as frequency and time-division multiplexing (FDM and TDM respectively).

From the methodology point of view, after a short briefing on what they are expected to do, the students are asked to classify the signal transmission techniques with the use of concept maps that (in order for the students to enhance their understanding) should also include possible interrelations among transmission techniques as well as reference to their use in specific telecommunication services and applications.

At present, this particular use of concept maps regards the Content Knowledge (CK) and Pedagogical Knowledge (PK) parts of the TPACK framework. The aim is for the students to develop Pedagogical Content Knowledge (PCK) in view of their possible future employment as secondary school teachers. Regarding Bloom’s revised taxonomy, the presentation mainly covers layers 2 and 3 (understand and apply) and maybe layer 4 (analyze). A future presentation could anticipate the formation and elaboration of concept maps with the use of computer tools that would also add the Technological Knowledge part (TK) and also enhance layer 4. The whole process anticipates and supports students’ active participation.

At the end of the lecture, a short questionnaire was distributed to students (three questions on the usefulness of concept maps) that should be answered by means of a 5-grade Likert scale (“1” strongly disagree, “2” disagree, “3” neither disagree nor agree, “4” agree, “5” strongly agree). The average in the answers was between 3.9 to 4.2 which shows that students generally agree on the value of concept maps as an educational tool.

Keywords:

Engineering Education, Electrical Engineering Education, Telecommunications, Concept Maps.