blems 11 Multiple Access Schemes What It Is The Underlying Ideas Example 11.1 Example 11.2 Introduction DS-CDMA FH-CDMA MC-CDMA Conclusion Problems 12 Analog Communications Modulation An Overview Amplitude Modulation (AM) AM Modulators in Time Example 12.1 AM Modulation in Frequency Demodulation of AM Signals Noise-Free Case An Alternative to AM DSB-SC Example 12.2 Frequency Modulation (FM) The Modulator in FM Example 12.3 The Demodulator in FM The Superheterodyne Receiver Summary Problems Annotated References and Bibliography Index Acknowledgments In this life of mine, I have been blessed with an abundance of won- derful people. This book would be incomplete without at least a page to say "thank you," for these are people alive in me and, therefore, alive in the pages of this book. Dr. Reza Soleymani, your careful guidance through the turmoil that surrounded my Ph.D. days was nothing short of a miracle. You showed me, through your example, how to handle even the most difficult of situations with grace and grit, both academically and in all of life. Dr. Derek Lile, Department Head at CSU-a young faculty could not ask for better guidance. Your thoughtfulness, caring, and gentle support have helped nurture the best of who I am. I am grateful. Steve Shattil, Vice President of Idris Communications, you are indeed a genius of a man whose ideas have inspired me to walk down new roads in the wireless world. Arnold Alagar, President of Idris, thank you for sharing the bigger picture with me, helping guide my research out of obscure journals and into a world full of opportunity. To both of you, I am grateful for both our technological partnerships and our friendships. Bala Natarajan and Zhiqiang Wu, my two long-time Ph.D. students, your support for my research efforts, through your commitment and dedication, has not gone unnoticed. Thank you for giving SO fully of yourselves. Dr. Maier Blostien, who asked me to change my acknowledgments page in my Ph.D. thesis to something less gushy, let me thank you now for saving the d