At what point does your circuit become "digital"?

[vk6zgo]

OK, I'm being pedantic, but this is one of my pet hates.
Everybody calls any rectangular wave a "square wave", but it  is not the case.

This might be a language issue. In many English speakingsly countries "square" is not just a specific polygon. It is also used as an adjective which means perpendicular, or even as an adjective to mean having 90 degree angles.

This could be one of those pet peeves you can let go of.

If you want to get really pendantic, voltage and time have no universal scale in relation to each other. Volts and seconds are arbitrary human units. Any "rectangular" half wave can be described as a 3-sided square (ignoring the rise/fall times) by tweaking the scale.

I think you are assuming that I am referring to how the waveform looks on a 'scope.
Obviously, the only time it really looks " square " in that sense is if you set the horizontal & vertical controls to look that way.

A rectangular waveform with a 50% duty cycle  has been referred to as a " square" wave for many decades by people working in Electronics.
(How "square "is used by the General Public is beside the point.)

OK, it is perhaps a misnomer, but the waveform has a substantially different spectra compared to other such waveforms.

If I really want to be pedantic, "pedantic"is not spelled "pendantic" .

[KL27x]

I have never heard  "square" used in the sense of square corners in over 40 years.

We run a board through a jointer and planer to square it. After it's done, the board is square. Perhaps that started out as "in square" or "[having been] squared," before turning into just "square." We adjust picture hanging on a wall until it is square. We square furniture with the walls. And when it's done, we could say, in context, that the bed is square [implicit that it is square in relation to something else].

In Australia you guys don't do that, eh?

After typing "square" so many times, I am starting to feel like square is a funny looking word.

The only sense I have ever heard [square] is a rectangular waveform with a 1:1 mark/space ratio (50% duty cycle)

I find that hard to believe.

The only sense I have ever heard ["square" in context of an electrical signal] is a rectangular waveform with a 1:1 mark/space ratio (50% duty cycle)

This is also obviously false. See your first post. You wouldn't have a pet peeve over this if you hadn't heard it used to describe other "rectangular" wave forms.

OTOH, I could say the first time I have consciously heard "rectangular" as describing an electrical signal was in this thread.

A rectangular waveform with a 50% duty cycle  has been referred to as a " square" wave for many decades by people working in Electronics.

Are you saying "rectangular wave" is the proper terminology? Maybe people got lazy and stopped saying it because it's too many syllables?

I think you are assuming that I am referring to how the waveform looks on a 'scope.

I am assuming that is how the name came to be. Why is a signal triangular, sawtooth, trapezoidal, etc? Why do you call a signal rectangular?  And why does "square" only apply to "rectangular" waves, if it has nothing to do with the shape of the voltage over time? Why not a square triangle wave (meaning triangle wave which is symmetrical)?

When I read Merriam Webster definition of "square wave" meaning only 50% duty cycle, I actually feel like it's wrong. I'm one of the new breed, I suppose. To me they are all square waves, and some have a 50% duty cycle. They're square because they are box shaped and the angles are square, which is irrespective of voltage and timebase settings (within reason... finite rise/fall times and all). I'm happy to evolve the language and fuel your pet peeve.

[vk6zgo]

I have never heard  "square" used in the sense of square corners in over 40 years.

We run a board through a jointer and planer to square it. After it's done, the board is square. Perhaps that started out as "in square" or "[having been] squared," before turning into just "square." We adjust picture hanging on a wall until it is square. We square furniture with the walls. And when it's done, we could say, in context, that the bed is square [implicit that it is square in relation to something else].

In Australia you guys don't
do that, eh?

OK, you got me on that.
I meant in an Electronic context, which seemed reasonable considering we are in a thread on an Electronics website.

After typing "square" so many times, I am starting to feel like square is a funny looking word.

The only sense I have ever heard [square] is a rectangular waveform with a 1:1 mark/space ratio (50% duty cycle)

I find that hard to believe.

The only sense I have ever heard ["square" in context of an electrical signal] is a rectangular waveform with a 1:1 mark/space ratio (50% duty cycle)

This is also obviously false. See your first post. You wouldn't have a pet peeve over this if you hadn't heard it used to describe other "rectangular" wave forms.

Yes, you are quite correct, I meant that I have never heard it used by people who know how to use the correct terminology.
Obviously, I have also heard it used incorrectly.

OTOH, I could say the first time I have consciously heard "rectangular" as describing an electrical signal was in this thread.

A rectangular waveform with a 50% duty cycle  has been referred to as a " square" wave for many decades by people working in Electronics.

Are you saying "rectangular wave" is the proper terminology? Maybe people got lazy and stopped saying it because it's too many syllables?

I think you are assuming that I am referring to how the waveform looks on a 'scope.

I am assuming that is how the name came to be. Why is a signal triangular, sawtooth, trapezoidal, etc? Why do you call a signal rectangular?  And why does "square" only apply to "rectangular" waves, if it has nothing to do with the shape of the voltage over time? Why not a square triangle wave (meaning triangle wave which is symmetrical)?

When I read Merriam Webster definition of "square wave" meaning only 50% duty cycle, I actually feel like it's wrong. I'm one of the new breed, I suppose. To me they are all square waves, and some have a 50% duty cycle. They're square because they are box shaped and the angles are square, which is irrespective of voltage and timebase settings (within reason... finite rise/fall times and all). I'm happy to evolve the language and fuel your pet peeve.

You can, of course, make up your own terminology.
The only downside is that people may not know what you are talking about!

[KL27x]

You can, of course, make up your own terminology.
The only downside is that people may not know what you are talking about!

If...

Everybody calls any rectangular wave a "square wave",

... this is not a very big risk. I think it's just as likely that people don't assume a "square wave" to automatically have a 50% duty cycle. Funny when you google "rectangular wave," 90% of the links returned are for "square wave." The proper terminology might come back into vogue one day, but the genie is out of the bottle. I was never aware of the proper terminology of rectangle/rectangular wave until this thread!

[james_s]

Something I think you may have all missed (I apologize if not) is the role of the dreaded PRODUCT MARKETING!

In my experience these people can call black, white if they think it will better attract the consumer.

There was a time before humble washing machines contained micro-processors that many goods that contained not a bit, were labelled digital. A bit like the Blue LED fad etc etc.

In certain quarters of the audiophile fraternity ANALOGUE is sought after and the presence of any digital components suppressed.

I'm reminded of Blip, "The digital game" which is in fact an ingenious mechanical contraption. The only electrical parts it contains are an LED, resistor, switch and battery. You don't see that sort of complex mechanical engineering in toys anymore.

[alanb]

At what point does your circuit become "digital"? -- When the marketing people say that it should!
Digital justifies a higher price than non-digital.

You will see that Dyson vacuum cleaners have 'Digital' motors, what ever that means.

[Beamin]

I think he's referring to the class of rectangular wave which is self-inverse.  In other words, duty cycle = 50%, and a spectrum of odd harmonics that go as 1/N.

I tend to use "square" in the "right" sense (square corners), hence "squaring up" a signal (using an amplifier and clipper, or comparator stage), and neglecting rise/fall times in that sense.  It's more accessible (less of a mouthful and more universally understood) than "trapezoidal wave", which would be more strictly correct (but really, the corners are rounded over, but really the..)

I have never heard  " square" used in the sense of square corners in over 40 years.
The only sense I have ever heard is a rectangular waveform with a 1:1 mark/space ratio (50% duty cycle)
(& yes, I neglected to change from 1:1 to 50% when I decided to use duty cycle instead of m/s ratio).

The spectrum of such a waveform is different from that of other rectangular waveforms of different duty cycle.
I recall having to work out the reason for the difference when I did the "retreads" course to become a Tech Officer with Telecom Aust.
The guys that ran the course were very hard on stuff like that.

You have never heard of squaring things up? Or square shoulders? Or squaring up to your opponent? Or "these edges are nice and square"? Or "That car looks more square?" I think you are an "L7" Its hip to be square. 

[vk6zgo]

I think he's referring to the class of rectangular wave which is self-inverse.  In other words, duty cycle = 50%, and a spectrum of odd harmonics that go as 1/N.

I tend to use "square" in the "right" sense (square corners), hence "squaring up" a signal (using an amplifier and clipper, or comparator stage), and neglecting rise/fall times in that sense.  It's more accessible (less of a mouthful and more universally understood) than "trapezoidal wave", which would be more strictly correct (but really, the corners are rounded over, but really the..)

I have never heard  " square" used in the sense of square corners in over 40 years.
The only sense I have ever heard is a rectangular waveform with a 1:1 mark/space ratio (50% duty cycle)
(& yes, I neglected to change from 1:1 to 50% when I decided to use duty cycle instead of m/s ratio).

The spectrum of such a waveform is different from that of other rectangular waveforms of different duty cycle.
I recall having to work out the reason for the difference when I did the "retreads" course to become a Tech Officer with Telecom Aust.
The guys that ran the course were very hard on stuff like that.

You have never heard of squaring things up? Or square shoulders? Or squaring up to your opponent? Or "these edges are nice and square"? Or "That car looks more square?" I think you are vean "L7" Its hip to be square.

I meant  "square" corners in the context of waveforms, as I pointed out in an earlier posting.

OK, maybe "square wave " for a 50% duty cycle  rectangular (or trapezoidal if you like) waveform is no more logical than any other naming convention, but it is the correct terminology, & should be recognised as such by people dealing with such waveforms.

There are many different cases of the correct name becoming that from long usage.
For instance, the thing called a Panzer in German is a "Tank" in English, for no real logical reason, apart from being the code name the Brits used for them in WW1.
Any Soldier will immediately recognise what you are talking about, but a farmer may think of something else, & an EE involved in RF work, something else entirely.