IQ Modulation in Frequency Domain
时间：04-06
整理：3721RD
点击：
Hi All,
I am trying to understand the concept of IQ modulation and is able to understand why the In Phase and Quadrature Phase components don't interfere in time domain but I am unable to see the same phenomena in frequency domain.
Suppose we want to transmit digital signal 11 using QPSK. In this case, our digital signal 1 will have a certain bandwidth (raised cosine). This baseband bandwidth will be transformed to a passband signal when multiplied by a In Phase carrier with frequency fc. Also the passband spectrum for the quadrature carrier will look the same centered as fc.
Now, when we add these two spectrum centered as fc, we should see the interference.
Can anybody please explain this contradiction or guide to a good tutorial.
[/img]
I am trying to understand the concept of IQ modulation and is able to understand why the In Phase and Quadrature Phase components don't interfere in time domain but I am unable to see the same phenomena in frequency domain.
Suppose we want to transmit digital signal 11 using QPSK. In this case, our digital signal 1 will have a certain bandwidth (raised cosine). This baseband bandwidth will be transformed to a passband signal when multiplied by a In Phase carrier with frequency fc. Also the passband spectrum for the quadrature carrier will look the same centered as fc.
Now, when we add these two spectrum centered as fc, we should see the interference.
Can anybody please explain this contradiction or guide to a good tutorial.
[/img]
http://www.newark.com/pdfs/techartic...modulators.pdf
page 6 and more
@vfone :- Thanks a lot. It was a joyride reading that article.
http://www.ni.com/white-paper/4805/en
basic introduction and good one too...!
Modulation IQ Domain 相关文章：