1. Sep 23, 2005CS477: Analog and Digital Communications1 Filtering and Bandpass Signals Analog and Digital Communications Autumn 2005-2006

2. Sep 23, 2005CS477: Analog and Digital Communications2 LTI Systems Revisited For random and deterministic signals: (Prove it at home!) (For real channels!)

3. Sep 23, 2005CS477: Analog and Digital Communications3 Example: Random Signal Consider White Noise input to an LTI filter LTI

4. Sep 23, 2005CS477: Analog and Digital Communications4 Example: Deterministic Signal (prove it yourself!)

5. Sep 23, 2005CS477: Analog and Digital Communications5 Example: Modulation Consider Modulation of a Random Signal (Prove it at home!)

6. Sep 23, 2005CS477: Analog and Digital Communications6 Bandpass Signals How does it look like in frequency domain? What might be an expression for the time domain signal? Two deltas (in frequency) convolved with a baseband/lowpass signal! A sinusoid multiplied with a baseband/lowpass signal!

7. Sep 23, 2005CS477: Analog and Digital Communications7 Bandpass Signals

8. Sep 23, 2005CS477: Analog and Digital Communications8 Lowpass-Bandpass Why this all lowpass-bandpass stuff needed?