正交訊號之特性及應用

Characterizations and Applications of Quadrature Signals

吳鳳珠(Feng-Ju Wu)

指導教授 ： 劉皆成

大同大學/電機資訊學院/通訊工程研究所/碩士(2005年)

摘要

正交處理技術為現代數位通信系統之核心科技，使用正交處理技術可將訊號由實數領域轉換為複數領域，即將二維訊號變為三維訊號。此可增加訊號處理上之自由度及彈性，且可能因此發展出新的技術及結構。
使用原型低通濾波器、以正交調變／解調原理，可獲得帶通濾波器。可調式帶通濾波器可使得原型低通IIR或 FIR濾波器，轉換成通帶在DC至Nyquist頻率之間的帶通濾波器。當高通或低通濾波器具有一足夠小的通帶(<0.5)時，其輸出為具兩倍頻寬之帶通濾波器。在數位無線個人行動通信系統中，可調式帶通濾波器可非常有效地用於消除寬頻帶通信中之窄頻帶干擾。

關鍵字

正交訊號、濾波器、可調式濾波器

並列摘要

Quadrature processing technique is the core technology of modern digital communication systems. The using of quadrature processing technique transforms the signal from real to complex domain, i.e., makes a two-dimensional signal to become a three-dimensional signal. That can enlarge the degree of freedom and flexibility on the processing of a signal, and thus many new techniques and fancy structures can be developed accordingly.
The bandpass filtering using a prototype lowpass filter is obtained by using the principles of quadrature modulation and demodulation. A tunable bandpass filter is presented that allows a prototype IIR or FIR filter to be shifted through the entire range of digital frequencies from DC to the Nyquist frequency. When a highpass or lowpass filter with a sufficiently small passband (<0.5), the resulting output is a bandpass filter with twice the bandwidth. In digital wireless personal mobile communication systems, the tunable bandpass filter can be used very effectively in the elimination of narrow band interference in wideband communications.

並列關鍵字

filter ； Quadrature Signals ； tunable filter

參考文獻

[1] Bernard Sklar, Digital Communications: Fundamentals and Applications, 2nd Edition 2001, Prentice Hall.

[2] John G. Proakis, Digital Communications, 2nd Edition, 1989, McGraw-Hill, Inc.

[7] “Digital Modulation in Communications Systems – An Introduction,” Application Note 1298, Hewlett Parckard.

[8] R.E. Crochiere and L. R. Rabiner, Multirate Digital Signal Processing, 1983, Prentice-Hall.

[10] A. V. Oppenheim and R. W. Schafer, Discrete-Time Signal Processing, 1989, Prentice-Hall.