his lesson covers the various modulation techniques used in mobile communications. It begins with a recap of linear digital modulation techniques and their advantages over analog modulation techniques. The lesson then delves into constant envelop modulation techniques, discussing their power efficiency and low out-of-band radiation. It explores Binary Frequency Shift Keying (BFSK), Minimum Shift Keying (MSK), and Gaussian Minimum Shift Keying (GMSK), explaining their workings, advantages, and applications. The lesson concludes with a brief introduction to M-ary Phase Shift Keying (PSK), setting the stage for future discussions on Quadrature Amplitude Modulation and Spread Spectrum Techniques.
01:11 - Introduction to modulation techniques for mobile communications
03:29 - Introduction to constant envelop modulation techniques and their advantages
08:35 - Introduction to continuous phase FSK
15:11 - Discussion on the power spectral density of FSK
22:18 - Explanation of the power spectral density of MSK
34:09 - Introduction to Gaussian minimum shift keying (GMSK)
38:14 - Introduction to M-ary PSK and its power spectrum
48:06 - Conclusion and summary of the lecture
- Linear digital modulation techniques are superior to analog modulation techniques due to their better performance in noisy environments.
- Constant envelop modulation techniques are power-efficient and produce low out-of-band radiation, making them ideal for mobile communications.
- Binary Frequency Shift Keying (BFSK) is a simple modulation technique where different frequencies represent different binary values.
- Minimum Shift Keying (MSK) is a more spectrally efficient modulation technique that reduces the frequency shift between symbols.
- Gaussian Minimum Shift Keying (GMSK) further improves the spectral efficiency of MSK by passing the modulating waveform through a Gaussian filter.
- M-ary Phase Shift Keying (PSK) is a modulation technique that allows for higher data rates by transmitting multiple bits per symbol.