1. S. Mandayam/ ECOMMS/ECE Dept./Rowan University Electrical Communications Systems ECE.09.331 Spring 2008 Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring08/ecomms/ Lab 2: Pre-lab Instruction

2. S. Mandayam/ ECOMMS/ECE Dept./Rowan University ECOMMS: Topics

3. S. Mandayam/ ECOMMS/ECE Dept./Rowan UniversityPlan Recall: AM Spectrum AM: Envelope Detector DSB-SC Modulation Systems Signals Complex Envelope Time Domain Spectrum Systems Balanced Modulator Coherent Detector Lab Project 2

4. S. Mandayam/ ECOMMS/ECE Dept./Rowan University Recall: AM Spectrum -B 0 +B |M(f)| f -f c -B -f c -f c +B 0 f c -B f c f c +B |S(f)| f Message Spectrum AM Spectrum

5. S. Mandayam/ ECOMMS/ECE Dept./Rowan University AM: Envelope Detector ~ + - + - + - v i (t) v o (t) RLRL s(t) Circuit Waveforms C s(t) t

6. S. Mandayam/ ECOMMS/ECE Dept./Rowan University DSB-SC Modulation Signals Systems Time Domain Complex Envelope Spectrum Power Performance Transmitters Receivers Standards Modulation Index Efficiency Bandwidth Noise -B 0 +B |M(f)| f -f c -B -f c -f c +B 0 f c -B f c f c +B |S(f)| f Message Spectrum DSB-SC Spectrum Matlab Demo http://engineering.rowan.edu /~shreek/spring08/ecomms/ demos/dsbsc.m

7. S. Mandayam/ ECOMMS/ECE Dept./Rowan University DSB-SC: Balanced Modulator AM A c cos2  f c t m(t) AM -A c cos2  f c t -m(t) 

8. S. Mandayam/ ECOMMS/ECE Dept./Rowan University DSB-SC: Coherent Detector Product Modulator A o cos2  f c t s(t) Local Oscillator Baseband LPF v(t)

9. S. Mandayam/ ECOMMS/ECE Dept./Rowan University Lab Project 2: AM and DSB-SC Modulation and Detection http://engineering.rowan.edu/~shreek/spring08/ecomms/lab2.html

10. S. Mandayam/ ECOMMS/ECE Dept./Rowan University Multi-tone Modulation -12 V DC 1k LM613 7 13 5 6 4 + - ~ AF from sound card o/p +12 V DC 1k 47k HP 33120A Arb. AM MODULATION (5V = 100%) 42V MAX Speakers HP 5465A Scope Envelope Detector FFT

11. S. Mandayam/ ECOMMS/ECE Dept./Rowan UniversitySummary