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If I'm converting something from analogue to digital, I digitise it.

What am I doing if I convert from digital to analogue?

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  • Comments are not for extended discussion; this conversation has been moved to chat. – tchrist Jan 16 '17 at 13:57
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    I wonder why this is considered off-topic? Some of the ensuing conversation about signal processing is off-topic, but that's been moved to chat anyway. – jpa Jan 17 '17 at 7:14

16 Answers 16

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You reconstruct, as in a reconstruction filter found in digital-to-analog converters:

a reconstruction filter is used to construct a smooth analog signal from a digital input

  • 1
    You aren't reconstructing, you're estimating, unless you have sufficient conditions—like a finite amount of bandwidth captured—which is probably impossible in real life. – Daniel van Flymen Jan 16 '17 at 6:11
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    Quite possible for many important use cases e.g. human threshold of hearing. See Nyquist theorem. – wim Jan 16 '17 at 7:06
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    Reconstruction can be an estimate. Like medical CT/PET and MRI where it's always called reconstruction and it's always been an estimate from the very beginning. Digitizing involves three processes: sampling (from signal to samples), quantizing (from samples to numbers), then encoding (from numbers to digits). Then D to A needs to reverse all three. Reconstruction is a good summary of the whole process. – user3528438 Jan 16 '17 at 16:32
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    reconstruction seems to be the way to go. See this wikipedia page: en.wikipedia.org/wiki/Digital-to-analog_converter – Florian Castellane Jan 16 '17 at 17:56
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    @FlorianCastellane Or better: en.wikipedia.org/wiki/Signal_reconstruction ... this is most certainly the right answer. – SusanW Jan 16 '17 at 18:45
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This is an interesting question.

The distinction between the two is characterised by the distinction between the discrete and the continuous. To take something discrete and make it continuous, one interpolates.

Dictonary.com defines interpolate as:

Mathematics. to insert, estimate, or find an intermediate term in (a sequence).

  • Comments are not for extended discussion; this conversation has been moved to chat. – tchrist Jan 16 '17 at 23:50
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I know of no such specific antonym to digitizing; however, by digitizing an analog signal, we are actually encoding it. And, so when we convert the digital signal back to analog for consumption, we are actually decoding it.

ODO:

decode VERB

[WITH OBJECT]
1.2 Convert (audio or video signals) into a different or usable form, for example to analogue from digital in sound reproduction

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    Again, being somewhat technical, sampling (which is really the process of digitizing) doesn't necessarily involve encoding. – TripeHound Jan 16 '17 at 15:34
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    as a signals processing major, I strongly disagree with this answer. – Florian Castellane Jan 16 '17 at 17:54
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    @FlorianCastellane yep, I strongly disagree too. It's like muddling "translating" and "comprehending": you might have to decode the digital encoding, but that's not the bit that necessarily involves anything to do with analogue reconstruction. – SusanW Jan 16 '17 at 18:09
  • Encoding does not necessarily imply encryption. Converting an analog signal into digital (numbers) is an encoding process. Think of a measuring cup, when you fill it to one of the lines, you have encoded that volume as a number (of units). Sampling is also a form of encoding, turning signals into numbers. Decoding is a valid term for converting the numbers (of units) back into analog. – Brent Washburne Jan 16 '17 at 21:51
  • @BrentWashburne: Encoding is rather close to being the opposite of encryption - it's formatting your data according to an a convention that facilitates (rather than hinders) comprehension of it. – R.. Jan 16 '17 at 22:35
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Perhaps the simplest solution here is to use the prefix "un-":

  • un-digitise
  • undigitise
  • (or their "z" equivalents)

Some might argue that a hyphenated word is not a single word, and some might suggest that the above is not a "real word"; however the verb "digitise" itself is a relatively new addition, and we all know that language evolves through the addition of new words just like this.

In fact, "undigitise" (or "undigitize") is beginning to gain some traction, although so far it tends to be used to refer to reducing one's reliance on technology rather than converting something from digital to analogue.

  • +1 This seems to be the only real antonym... – Mehrdad Jan 17 '17 at 0:18
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In a context where digitize means "quantize and record digital samples of a continuous-valued signal", the verb for going the other direction is to reproduce the signal from the samples. I wouldn't say it fills in the blank in the subject-line of your question, but it's often the word that fits in actual usage.

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    But reproduce is ambiguous because you can reproduce digitally by file copying, or you can reproduce in analogue by printing or playing the digital sound recording. – Chris Rogers Jan 16 '17 at 8:07
  • @Chris: That's part of what I mean by it not fitting the fill-in-the-blank. It needs context. FWIW I generally wouldn't use reproduce for making an exact copy of a digital file except perhaps in the case of data protected by an error correcting code where I was missing part of the original and used the code to recreate the missing bits (thereby reproducing the file). – R.. Jan 16 '17 at 13:32
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I believe the word you are looking for is "render". It has a variety of applications mostly having to do with converting something into something else or with the creation of art or graphic design either in physical or virtual form.

5

It doesn't matter what the analogue source is (sound, image or text) when using the word digitise (British English) or digitize (American English) however going the other way (from digital to analogue), the words used would depend on the resulting analogue output.

For images, text, or 3D object, it would be print

For audio it would be sound

verb (used without object)

  1. to make or emit a sound.

  2. to give forth a sound as a call or summons:
    The bugle sounded as the troops advanced.

verb (used with object)

  1. to cause to make or emit a sound: to sound a bell.

  2. to give forth (a sound):
    The oboe sounded an A.

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    Re sound, hearing depends on an analog process, so anything that plays a digital file so you can hear it is automatically converting it to analog. – barbecue Jan 16 '17 at 19:57
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Similar to this answer (undigitise), I'd use

de-digitise or it's z-equivalent, de-digitize

Examples of similar constructions are compress / decompress and escalate / de-escalate.

3

Digital is to digitise, as analogue is to smooth - to transform or modify (a graph, distribution, or function) so as to make it smooth; to lessen irregularities or fluctuations in (something that can be represented by a graph)(OED).

The OP asks

What am I doing when I convert something from digital to analogue? (i.e. when I produce continuously variable physical quantities (OED) from a series of discrete measurements).

'Smoothing', by some form of interpolation, describes in lay terms 'what I am doing' - making continuously variable physical quantities from a series of discrete measurments.

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    I believe what you have is the opposite of "discretize" or "quantize", not "digitize"? – Mehrdad Jan 16 '17 at 4:47
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    @Mehrdad - aren't "digitize" and "quantize" synonyms? Digitize -> render as numeric values (with clear implication of a limited range of possible numbers); quantize -> convert into a limited set of possible values. I can't see any clear distinction between the two. – Periata Breatta Jan 16 '17 at 10:51
  • @Mehrdad - please can you clarify the distinctions you are making between discretise, quantise and digitise. – Dan Jan 16 '17 at 11:14
  • There are lots of reasons why these aren't the same, some more technical than others. But to give you an idea without worrying about being 100% technically accurate: imagine a hot sheet of metal whose temperature you're trying to measure. First you might "discretize" the sheet by chopping it up into little pieces. Then you might "quantize" each piece's temperature by touching your old-fashioned alcohol-based thermometer to it and marking the closest square on the graph paper beside it. Finally you might "digitize" your results by expressing them as numbers. All these steps are independent. – Mehrdad Jan 16 '17 at 12:58
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    ...Important takeaways: (1) discretization does not necessarily even involve values or numbers... you can discretize anything, even your sandwich, (2) quantization is arguably about approximation and therefore involves numeric values, but doesn't concern itself with how those values are represented (the grid lines you marked on paper are not themselves numbers/digital; they're merely quantizations of what you measured), and (3) digitization doesn't necessarily even involve approximation (y = x * x is a 5-character digital description of a smooth curve). @PeriataBreatta – Mehrdad Jan 16 '17 at 13:16
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To critique your question, I don't think "digitize" is an acceptable verb since it's ambiguous and non-technical. The word discretize would be more apt, since what you're actually describing is an arbitrary function or process which takes values from the discrete to the continuous. And to perform that process, we estimate a continuous range of values between two known discrete points.

In short, the word you're looking for is interpolate.

From Wikipedia:

In the mathematical field of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points.

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    Not sure about this at all. Interpolation doesn't imply converting to analogue: it's just a necessary step towards analogue reconstruction. I could just be re-sampling to change the data rate. – SusanW Jan 16 '17 at 18:20
  • "Digitize" is absolutely an acceptable verb. You read too much into the OP's question by assuming that he isn't looking for a technical term, and you also consider this a technical term even though it is one which is used by non-technical people for non-technical reasons. – Beanluc Jan 16 '17 at 18:59
  • Rather than assuming the OP is or is not looking for a technical term, let's ask him – barbecue Jan 16 '17 at 19:31
  • @SusanW You're right, interpolation doesn't necessarily imply conversion to analogue but conversion to analogue definitely implies interpolation. – Daniel van Flymen Jan 17 '17 at 2:51
  • @Beanluc "Digitize" is pretty broad, and so I felt that "discretize" is more precise and technical since the OP is asking for clarification of a process. But I'm happy to amend my answer if they reply here. – Daniel van Flymen Jan 17 '17 at 2:56
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Analogize. You are making an "analog" of the original source by way of a digital sampling.

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    + 1. It follows the standard pattern (seen in humanize, vaporize etc.). Of course another meaning has preempted the word. But there is no reason the word shouldn't have a second meaning. It might come to if digital-to-analogue conversion became as commonplace as analogies. / Most of the other answers are describing what happens when you analogize (in our new sense), not naming the process. – Catomic Jan 17 '17 at 5:07
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You might be talking about moving from one storage\playback protocol\format to another.

e.g Convert a .mp3 music file (compressed, lossy) to .wav (bitmap, uncompressed, lossless)

In that case you would say you were re-encoding or converting it to another format\protocol.

VLC, for example, uses the term convert.

0

"Convert".

An analog-to-digital converter digitizes, but what a digital-to-analog converter does is, it converts.

This is assuming that what you want to capture in your analog medium is something which is already in digital format. If it's not, then what you want to do is to simply "record" it.

0

When I take a digital video or sound source and convert it to analog (for example by using a tape recorder to record an MP3) I am making an analog recording of the digital source.

In earlier decades, recording a sound almost always meant making an analog recording by magnetic tape. For example, I might record a meeting with a tape recorder, or have a tape recording of a phone message on my answering machine.

When digital recording started to become affordable and mainstream, the word digital was added to indicate that digital techniques were being used instead of the default analog (and of course for marketing reasons.)

"Hey check out my new digital voice recorder, I can record a whole day of classes without having to change a tape!"

Fast forward to today, and digital recording is standard, while analog is the unusual special case. Today, recording is assumed to be digital, unless you specify otherwise by saying it's an analog recording.

0

In most everyday situations it depends on the medium.

My photo camera collects light and digitizes the amount at each pixel to obtain a picture file. To go back to analog I display the picture. My video camera does something similar, but I play back the video. The sound wave digitized to an audio file (whether compressed or not, lossy or lossless doesn't matter) gets played back, too. The sheet of paper digitized by your fax machine gets printed by my fax machine. The geographic position digitized by my GPS device can be marked on a map, or perhaps I want to visualize a whole track. The position of my stylus on my digitizer board (or your touch device) tends to stay digital, although it might well be used to manipulate things that find their way back into the analog world.

But even for these media, the words above are not truly the opposite of digitize. For each of them, a more common term would be the more obvious counterpart. You take a picture, record a video or audio, scan a sheet of paper, and perhaps log GPS positions. So if people use digitize instead of these, they do so for a reason. Here are some reasons I can imagine:

  1. to encompass different media.

    In this case I think render or reproduce would be most fitting. Both of these terms can mean other things, so they will require context or explanation.

  2. to sound technically up to date.

    In this case you have to make a decision. You can either use one of the terms I just suggested, without additional context, and hope people will understand what you mean. You can provide more context, thus making your statement longer. Or you can use the more established everiday terms, and risk sounding understandable boring.

  3. to focus on the specific properties of a digitizing operation.

    Here the mathematical aspects mentioned in other answers come into play. Perhaps you are worried about the loss of detail due to the digitization process, and want to counter that using interpolation? But then your real problem is more specifically with discretization (usually in the domain, e.g. finitely many distinct pixels) and quantization (usually in the range, e.g. finitely many different color values). So again it's not an exact pair of antonyms.

  4. to describe something without physical representation.

    I believe there are people who would use the term digitize when ripping an already digital DVD to a file on their computer. In that case, “digital” is (imprecisely) used to mean something without physical manifestation. You don't have a disc any more, and your computer looks the same as it did before you got the file. In this situation, a proper opposite would focus on the material aspects of the analog representation. You might call your printout (of a scanned sheet or a picture you took) a hardcopy, but I can't think of a verb for this.

0

One possibility would be

analog (analogue)

modeled after catalog (catalogue) and log, each a verb.

I also like the answer analogize given by DoritoStyle (modeled on humanize etc.).

The virtue of these possibilities is that they fit an established pattern.

A drawback may be that they already have established usages.

Of course my answer proposes a usage rather than identify one.

Some of the other answers seem to describe what happens in a digital-to-analog conversion rather than name the process.

  • "Some of the other answers seem to describe what happens in a digital-to-analog conversion rather than name the process." That is because the process has no name other than digital-to-analog conversion - which is already well established. – michael.hor257k Jan 17 '17 at 6:25

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