What is decimation

In practice, this usually implies lowpass-filtering a signal, then throwing away some of its samples. The decimation factor is simply the ratio of the input rate to the output rate. Exercise for the student: which letter is used as the symbol for interpo- L -ation factor? 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.

For example, if you double the sample rate, an equivalent filter will require four times as many operations to implement. This is because both amount of data per second and the length of the filter increase by two, so convolution goes up by four.

Thus, if you can halve the sample rate, you can decrease the work load by a factor of four. Decimation involves throwing away samples, so you can only decimate by integer factors; you cannot decimate by fractional factors. This just boils down to applying the Nyquist criteria to the input signal, relative to the new sampling rate. For example, suppose you have a signal sampled at a rate of 30 kHz, whose highest frequency component is 10 kHz which is less than the Nyquist frequency of 15 kHz.

If you wish to reduce the sampling rate by a factor of three to 10 kHz, you must ensure that you have no components greater than 5 kHz, which is the Nyquist frequency for the reduced rate. However, since the original signal has components up to 10 kHz, you must lowpass-filter the signal prior to downsampling to remove all components above 5 kHz so that no aliasing will occur when downsampling. You get aliasing—just as with other cases of violating the Nyquist criteria.

Aliasing is a type of distortion which cannot be corrected once it occurs. Yes, so long as the decimation factor, M, is not a prime number. For example, to decimate by a factor of 15, you could decimate by 5, then decimate by 3. The more prime factors M has, the more choices you have. For example you could decimate by a factor of 24 using:.

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But in the more common case of decimating combining filtering and downsamplingthe computational and memory requirements of the filters can usually be reduced by using multiple stages. The multirate book references give additional, more specific guidance. For example, to decimate by 4, keep every fourth sample, and throw three out of every four samples away.

You may be onto something. In the case of FIR filters, any output is a function only of the past inputs because there is no feedback. Therefore, you only have to calculate outputs which will be used. Depending on the filter topology used, certain feed-forward parts of the calculation can be omitted. The fact that only the outputs which will be used have to be calculated explains why decimating filters are almost always implemented using FIR filters!

Therefore, the larger the decimation factor is, the larger the savings, percentage-wise. A simple way to think of the amount of computation required to giant gx28 price a FIR decimator is that it is equal to the computation required for a non-decimating N-tap filter operating at the output rate.

what is decimation

A decimating FIR is actually the same as a regular FIR, except that you shift M samples into the delay line for each output you calculate. More specifically:. Also, just as with ordinary FIRs, circular buffers can be used to eliminate the requirement to literally shift the data in the delay line.

Just download and install the ScopeFIR distribution file. The major DSP vendors provide examples of FIR decimators in their data books and application notes; check their web sites.But the site has seen little of the decimation from heavy tourism that has plagued the northern pyramids of Giza in Egypt. In Texas, the grave consequences of the decimation of state family-planning funds in are already evident. During the daily decimation of the people's lives, he thought a daily decimation of their industry possible.

The Shirt-tail battalion and the bluegrass battalion stood in peril of decimation in their maiden engagement. Then the figure-four trap springs up in the hedgerow and the sedge while the work of decimation goes more rapidly along. What is our compensation for the decimation of our young men? This would make the loss over eleven per cent. Commas mark divisions in sentences. Periods end declarative sentences. Apostrophes show possession. Easy, right? Well, punctuation can get pretty tricky—fast.

Think you got what it takes to be a punctuation expert? Take our quiz to prove it! Which of the options below is the best punctuation for the sentence? Because the etymological sense of one-tenth remains to some extent, decimate is not ordinarily used with exact fractions or percentages: Drought has destroyed not decimated nearly 80 percent of the cattle.

Words nearby decimate decimal placedecimal pointdecimal systemdecimalizedecimalsdecimatedecimeterdecimetredecimusdecinormaldecipher. Words related to decimation murderslaughterbloodbathgenocideexterminationcarnagebloodshedassassinationliquidationeradicationeliminationextinctiondemolitiondestructionbloodlettingbutcheryannihilationmassacreholocaustdevastation.

Example sentences from the Web for decimation But the site has seen little of the decimation from heavy tourism that has plagued the northern pyramids of Giza in Egypt. Blackwood's Edinburgh Magazine, Volume 65, No. Andersonville, Volume 2 John McElroy.

Derived forms of decimate decimationnoun decimatornoun.But the site has seen little of the decimation from heavy tourism that has plagued the northern pyramids of Giza in Egypt. In Texas, the grave consequences of the decimation of state family-planning funds in are already evident.

During the daily decimation of the people's lives, he thought a daily decimation of their industry possible. The Shirt-tail battalion and the bluegrass battalion stood in peril of decimation in their maiden engagement.

Then the figure-four trap springs up in the hedgerow and the sedge while the work of decimation goes more rapidly along. What is our compensation for the decimation of our young men? This would make the loss over eleven per cent. Take this quiz on the Words of the Day from April 6—12 to find out!

Because the etymological sense of one-tenth remains to some extent, decimate is not ordinarily used with exact fractions or percentages: Drought has destroyed not decimated nearly 80 percent of the cattle. Words nearby decimate decimal placedecimal pointdecimal systemdecimalizedecimalsdecimatedecimeterdecimetredecimusdecinormaldecipher. Words related to decimation murderslaughterbloodbathgenocideexterminationcarnagebloodshedassassinationliquidationeradicationeliminationextinctiondemolitiondestructionbloodlettingbutcheryannihilationmassacreholocaustdevastation.

Example sentences from the Web for decimation But the site has seen little of the decimation from heavy tourism that has plagued the northern pyramids of Giza in Egypt. Blackwood's Edinburgh Magazine, Volume 65, No. Andersonville, Volume 2 John McElroy. Derived forms of decimate decimationnoun decimatornoun.To destroy or kill a large part of a group of people or organisms. Usage Problem a. To inflict great destruction or damage on: The storm decimated the region.

To reduce markedly in amount: a profligate heir who decimated his trust fund. To select by lot and kill one in every ten of a group of soldiers. Usage Note: Decimate originally referred to the killing of every tenth person, a punishment used in the Roman army for mutinous legions.

Today this meaning is commonly extended to include the killing of any large proportion of a population. In our survey, 81 percent of the Usage Panel accepts this extension in the sentence The Jewish population of Germany was decimated by the war, even though it is common knowledge that the number of Jews killed was much greater than a tenth of the original population.

This is an increase from the 66 percent who accepted this sentence in our survey. However, the Panel is less accepting of usages that extend the meaning to include large-scale destruction other than killing, as in The supply of fresh produce was decimated by the nuclear accident at Chernobyl.

Some 36 percent accepted this sentence inup from 26 percent inbut still a decided minority. Military esp in the ancient Roman army to kill every tenth man of a mutinous section.

what is decimation

Usage: One talks about the whole of something being decimated, not a part: disease decimated the population, not disease decimated most of the population.

Because the etymological sense of one-tenth remains to some extent, decimate is not ordinarily used with figures: Drought has destroyed not decimated 80 percent of the herd.

Switch to new thesaurus. In current language, however, the meaning of the word has broadened and it is now used not only to describe the destruction of people and animals, but also of institutions: overseas visitors will stay away in droves, decimating the tourist industry. Synonyms such as destroy for sense 1 and reduce for sense 2 are appropriate alternatives but because decimate should be used with regards to effects on the whole of something, rather than a part, it does not work as a synonym for them.

To kill savagely and indiscriminately: annihilatebutchermassacreslaughter. The population was decimated by the plague. Mentioned in? References in classic literature?And now, the plan is not only to decimate public-sector unions, but all unions—to deplete the money they can spend on politics.

And, from the south, chronic wasting disease is poised to decimate the elk herds. When we decimate the funding for hospital preparedness, we put ourselves in great peril. Instead we must decimate the mid-level leadership ISIS relies on. This was an ominous hint that he intended to decimate them, after the fashion of Field-Marshal Liposcak.

But Mr. Downing saw in his attack the beginnings of some deadly scourge which would sweep through and decimate the house. They had, therefore, no fear that the Hungarians could scale the walls and decimate their scanty band.

Pennant had previously noticed how spring fever used to decimate the west coast. Suddenly a terrible plague broke out in the city, and threatened to decimate the population.

Take this quiz on the Words of the Day from April 6—12 to find out! Because the etymological sense of one-tenth remains to some extent, decimate is not ordinarily used with exact fractions or percentages: Drought has destroyed not decimated nearly 80 percent of the cattle.

Words nearby decimate decimal placedecimal pointdecimal systemdecimalizedecimalsdecimatedecimeterdecimetredecimusdecinormaldecipher. Words related to decimate obliterateannihilateslaughterexterminateexecutemassacrebutcher. Example sentences from the Web for decimate And now, the plan is not only to decimate public-sector unions, but all unions—to deplete the money they can spend on politics.

Who the U. Mike P. The Strong Arm Robert Barr. Dixon, F.

Decimation (Roman army)

The Catholic World. Volume III; Numbers 1, 2, 3, 4, 5, 6. Derived forms of decimate decimationnoun decimatornoun. Test Your Word IQ! Play Now.To save this word, you'll need to log in. The connection between decimate and the number ten harks back to a brutal practice of the army of ancient Rome. A unit that was guilty of a severe crime such as mutiny was punished by selecting and executing one-tenth of its soldiers, thereby scaring the remaining nine-tenths into obedience.

It's no surprise that the word for this practice came from Latin decem, meaning "ten. In its extended uses decimate strayed from its "tenth" meaning and nowadays refers to the act of destroying or hurting something in great numbers.

Examples of decimate in a Sentence This kind of moth is responsible for decimating thousands of trees in our town. Budget cuts have decimated public services in small towns. Recent Examples on the Web Not just because of the razor-thin margins restaurants run on that can be decimated with a day or a week let alone weeks or months of no or limited business.

Send us feedback. See More First Known Use of decimatein the meaning defined at sense 1 History and Etymology for decimate Latin decimatuspast participle of decimarefrom decimus tenth, from decem ten Keep scrolling for more Learn More about decimate Share decimate Post the Definition of decimate to Facebook Share the Definition of decimate on Twitter Time Traveler for decimate. If You Like to Complain About You'll love to hate these other words! Regarding the Incorrect Use of Regarding the Incorrect Use of 'Decimate' It's totally fine to use 'decimate' as a synonym for 'devastate'.

This is why. Dictionary Entries near decimate decimal place decimal point decimal system decimate decimated decimating factor decimeter.

Downsampling (signal processing)

Accessed 14 Apr. Keep scrolling for more More Definitions for decimate decimate. Please tell us where you read or heard it including the quote, if possible. What does capricious mean? Test Your Knowledge - and learn some interesting things along the way.

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! When is 'whom' the right choice? And who put it there, anyway? What's with his feathered cap? Literally How to use a word that literally drives some people nuts. Is Singular 'They' a Better Choice?

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what is decimation

Can you spell these 10 commonly misspelled words? Do you know the person or title these quotes describe?In digital signal processingdownsamplingcompressionand decimation are terms associated with the process of resampling in a multi-rate digital signal processing system. Both downsampling and decimation can be synonymous with compressionor they can describe an entire process of bandwidth reduction filtering and sample-rate reduction. Decimation is a term that historically means the removal of every tenth one.

This factor multiplies the sampling interval or, equivalently, divides the sampling rate. A system component that performs decimation is called a decimator.

Decimation by an integer factor is also called compression. Rate reduction by an integer factor M can be explained as a two-step process, with an equivalent implementation that is more efficient: [5]. Step 2 alone allows high-frequency signal components to be misinterpreted by subsequent users of the data, which is a form of distortion called aliasing.

Step 1, when necessary, suppresses aliasing to an acceptable level. In this application, the filter is called an anti-aliasing filterand its design is discussed below. Also see undersampling for information about decimating bandpass functions and signals.

When the anti-aliasing filter is an IIR design, it relies on feedback from output to input, prior to the second step. With FIR filteringit is an easy matter to compute only every M th output.

what is decimation

The calculation performed by a decimating FIR filter for the n th output sample is a dot product: [b]. Impulse response coefficients taken at intervals of M form a subsequence, and there are M such subsequences phases multiplexed together. Thus M low-order FIR filters are each filtering one of M multiplexed phases of the input stream, and the M outputs are being summed. This viewpoint offers a different implementation that might be advantageous in a multi-processor architecture.

In other words, the input stream is demultiplexed and sent through a bank of M filters whose outputs are summed. When implemented that way, it is called a polyphase filter. The equivalence of this inefficient method and the implementation described above is known as the first Noble identity.

Decimation - One Of The Worst Forms of Punishment In Ancient Roman Military History

Let X f be the Fourier transform of any function, x twhose samples at some interval, Tequal the x [ n ] sequence. The periodic summation has been reduced in amplitude and periodicity by a factor of M. An example of both these distributions is depicted in the two traces of Fig 1. The purpose of the anti-aliasing filter is to ensure that the reduced periodicity does not create overlap.

Step 1 requires a lowpass filter after increasing expanding the data rate, and step 2 requires a lowpass filter before decimation. Therefore, both operations can be accomplished by a single filter with the lower of the two cutoff frequencies. From Wikipedia, the free encyclopedia. Redirected from Decimation signal processing. In practice the cutoff frequency is placed far enough below the theoretical cutoff that the filter's skirt is contained below the theoretical cutoff.

Discrete-Time Signal Processing 2nd ed. Upper Saddle River, N. EE Times. Retrieved The process of reducing a sampling rate by an integer factor is referred to as downsampling of a data sequence. We also refer to downsampling as decimation. The term decimation used for the downsampling process has been accepted and used in many textbooks and fields. Multirate Digital Signal Processing. September Handbook of Formulas and Tables for Signal Processing 1 ed.

CRC Press.


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