PSpice for Digital Communications Engineering (Paperback)

PSpice for Digital Communications Engineering shows how to simulate digital communication systems and modulation methods using the very powerful Cadence Orcad PSpice version 10.5 suite of software programs. Fourier series and Fourier transform are applied to signals to set the ground work for the modulation techniques introduced in later chapters. Various baseband signals, including duo-binary baseband signaling, are generated and the spectra are examined to detail the unsuitability of these signals for accessing the public switched network. Pulse code modulation and time-division multiplexing circuits are examined and simulated where sampling and quantization noise topics are discussed. We construct a single-channel PCM system from transmission to receiver i.e. end-to-end, and import real speech signals to examine the problems associated with aliasing, sample and hold. Companding is addressed here and we look at the A and mu law characteristics for achieving better signal to quantization noise ratios. Several types of delta modulators are examined and also the concept of time divisionmultiplexing is considered. Multi-level signaling techniques such as QPSK andQAMare analyzed and simulated and home-made meters, such as scatter and eye meters, are used to assess the performance of these modulation systems in the presence of noise. The raised-cosine family of filters for shaping data before transmission is examined in depth where bandwidth efficiency and channel capacity is discussed. We plot several graphs in Probe to compare the efficiency of these systems. Direct spread spectrum is the last topic to be examined and simulated to show the advantages of spreading the signal over a wide bandwidth and giving good signal security at the same time.

《PSpice for Digital Communications Engineering》展示了如何使用功能強大的Cadence Orcad PSpice 10.5軟體套件來模擬數位通訊系統和調變方法。傅立葉級數和傅立葉變換被應用於信號上，為後續章節介紹的調變技術奠定基礎。生成各種基頻信號，包括二元基頻信號，並檢查其頻譜以詳細說明這些信號在接入公共交換網絡方面的不適用性。對脈衝編碼調變和時分多路復用電路進行檢查和模擬，並討論了取樣和量化噪聲的問題。我們從傳輸到接收器（即端到端）構建了一個單通道脈衝編碼調變系統，並導入真實語音信號以檢查與混疊、取樣和保持相關的問題。在這裡討論了壓縮擴展技術，並研究了實現更好的信號與量化噪聲比的A和μ律特性。我們檢查了幾種類型的增量調製器，並考慮了時分多路復用的概念。分析和模擬了多級調變技術，如QPSK和QAM，並使用自製的儀表，如散射和眼圖儀表，來評估這些調變系統在噪聲存在下的性能。深入研究了用於在傳輸前塑形數據的升餘弦濾波器家族，討論了頻寬效率和信道容量。我們使用Probe繪製了幾個圖形，以比較這些系統的效率。最後，我們檢查並模擬了直接展頻技術，以展示在寬頻上展開信號的優勢，同時提供良好的信號安全性。