[google: "DSP decimation"] "Decimation is the process of filtering and downsampling a signal to decrease its effective sampling rate, as illustrated in figure 1. The filtering is employed to prevent aliasing that might otherwise result from downsampling." http://cnx.org/content/m10445/latest/
and http://www.dspguru.com/info/faqs/multrate/decim.htm 2.1 Basics 2.1.1 What are "decimation" and "downsampling"? Loosely speaking, "decimation" is the process of reducing the sampling rate. In practice, this usually implies lowpass-filtering a signal, then throwing away some of its samples. "Downsampling" is a more specific term which refers to just the process of throwing away samples, without the lowpass filtering operation. Throughout this FAQ, though, we'll just use the term "decimation" loosely, sometimes to mean "downsampling". 2.1.2 What is the "decimation factor"? The decimation factor is simply the ratio of the input rate to the output rate. It is usually symbolized by "M", so input rate / output rate=M. Tip: You can remember that "M" is the symbol for decimation factor by thinking of "deci-M-ation". (Exercise for the student: which letter is used as the symbol for interpo-L-ation factor?) 2.1.3 Why decimate? The most immediate reason to decimate is simply to reduce the sampling rate at the output of one system so a system operating at a lower sampling rate can input the signal. But a much more common motivation for decimation is to reduce the cost of processing: the calculation and/or memory required to implement a DSP system generally is proportional to the sampling rate, so the use of a lower sampling rate usually results in a cheaper implementation. n3hkn wrote: > I do not understand the use of "decimation" in the context of DSP > software. The dictionary only refers to it as killing every tenth > person. ??????? > > Dick N3HKN ------------------------ Yahoo! Groups Sponsor --------------------~--> Something is new at Yahoo! Groups. Check out the enhanced email design. http://us.click.yahoo.com/SISQkA/gOaOAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
