BibTeX
@MISC{Rx_singlechip,
author = {Direct-conversion Rx},
title = {Single Chip Realizes},
year = {}
}
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Abstract
nent count, along with the elimination of expensive fil-tering has made direct con-version very appealing as an architecture for transmit and receive functions. However, it is only recently that components which facilitate its practical implementation have become available. Although the direct-conversion approach reduces the component count, it also adds design challenges. In the super-heterodyne approach (Fig. 1, left), by driving the mixer with a frequency-agile LO, the frequency of the desired signal or channel (which is generally varies in a multi-user system) is converted to a fixed frequency. Once the desired signal has been converted to a fixed IF, it can be processed by highly selective narrowband filtering using a surface-acoustic-wave (SAW) filter. In addi-tion, all subsequent frequency transla-tions can be effected using fixed-frequency LOs. The other important function per-formed at IF in a superheterodyne sys-tem is signal amplification. Fixed-gain amplification, in the form of low-noise amplifiers (LNAs), is generally applied at RF, while signal leveling is general-
Keyphrases
single chip realizes desired signal multi-user system signal leveling practical implementation component count fixed frequency fixed-frequency los subsequent frequency transla-tions signal amplification nent count receive function selective narrowband design challenge superheterodyne sys-tem low-noise amplifier frequency-agile lo expensive fil-tering direct-conversion approach fixed-gain amplification important function per-formed super-heterodyne approach
