Class AB and Class D market share?

wwenze

Member
2008-03-07 12:46 pm
numbers are nothing, I can tell you that only the sound that goes out of speaker is valid, and many will tell you "analog is warmer", by warmer meaning sound... I am not a fan of AB, but they could have a point there

Eh... market share has nothing to do with technical performance of product e.g. iPod has largest market share, if that's what TS wanted to know.
 

RiskCord

Member
2008-04-16 11:25 pm
Yes, as wwenze says, I'm not talking about performance comparision, but simple figures like the ratio between the number of Class D amplifiers that have been sold last year and the number of Class B, AB...

The reason for asking this is that I have the impression (I might be wrong, of course) that Class D are still not widely known and even less widely accepted. Of course most of you here are as familliar with Class D amps as with your own hands (ok, I might be exaggerating :D) but for what I've experience in other "technical circles" it is not the case. Most people I have surveyed have "kinda heard" something about Class D, they know it is a switched amplifier and they thing that D stands for digital... I have checked on internet and I havent found any convincing figures.

Anyway, the topic keeps open...
 
Yes, as wwenze says, I'm not talking about performance comparision, but simple figures like the ratio between the number of Class D amplifiers that have been sold last year and the number of Class B, AB...

The reason for asking this is that I have the impression (I might be wrong, of course) that Class D are still not widely known and even less widely accepted. Of course most of you here are as familliar with Class D amps as with your own hands (ok, I might be exaggerating :D) but for what I've experience in other "technical circles" it is not the case. Most people I have surveyed have "kinda heard" something about Class D, they know it is a switched amplifier and they thing that D stands for digital... I have checked on internet and I havent found any convincing figures.

Anyway, the topic keeps open...

I don't know the exact numbers, but the original question isn't very specific either.
When batery-operated devices are considered, like mobile phones, than class D wins. In PA systems class G/H and switched/linear hybrids are doing surpisingly well in terms of sales.
In home hi-fi class AB is still having most of the market and it is questionable if there is much point in having, say, a 25W class D amplifier in a home stereo.
But I've seen new dirty class B amplifiers in applications, where class D would perform much better and be way cheaper, that's still a matter of time and market inertia.
 
ClassD is a switching amplifier that can use Pulse Modulation to create sort of squarewaves that have an average power roughly equivalent to the analogue voltage we had in the input signal.

That switched signal is very similar to the 0s and 1s that are binary. Thus we have the confusion that the ClassD is digital.

Analogue it certainly is not.
 
If the signal parameter wich carries the information can have any value, then it's analog, if it can have only some certain value, then it's digital. In a Class D amp the information carrier parameter is generally the pulse width. This can be analog or quantized (digital) too.

For those who has doubts: is FM digital? After the limiter it is square wave too!
 
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wwenze

Member
2008-03-07 12:46 pm
Signals are just signals... it's only possible to send a waveform, not 0s and 1s. It's how the signal is sampled that matters - if the receiver requires it to have certain voltages for true and certain voltages for false, then it is sampled digitally. Else, analogue. But even so, there can be confusion, for example, is voltage ladder ADC considered digital or analogue, sure it is an A-D converter, but instead of just one and zeros it can have values of 2 to 15. :headshot:

So to answer the above question, FM is a sine-ish wave clipped to look square after the limiter, but it is sampled as analogue.

Well, you can even ask if the square wave played through the speakers is analogue or digital. :D
 
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Bernie7

Member
2008-12-21 4:04 pm
Isn't digital defined by info that's carried in binary coded (not incidental) state, and once it ceases to be in that state, it's analog (whatever it is, it's certainly not digital).

In Class D PWM, does any manufacturer today reduce the signal to coded binary so that the usual digital error correction routines may be applied?

Square waves, saw-tooth waves, various carrier waves and their modulation schemes (FM. AM or PWM) are irrelevant. Leave aside the issue of what's possible - anything is possible in time, one day we may sprout wings too! If PWM today handles and processes the signal in the coded binary state, I might accept that Class D amps are digital too.
 
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Bernie7!

If PWM today handles and processes the signal in the coded binary state, I might accept that Class D amps are digital too.

2 examples:
- All (or almost all) ClassD amps of TI processes digital signal until the last (power) stage.
- PIC's and others microcontrollers have in-built PWM modulator wich is definitely digital.

This doesn't mean Class D is digital. Class doesn't tell anything about this.

Isn't digital defined by info that's carried in binary coded (not incidental) state,

Don't confuse digital and binary! Digital=the way you count on your fingers. (Natural numbers.) Digitus(lat)=finger. Binary=one digit is from a set with two members.

wwenze!

It's how the signal is sampled that matters

What if it is not sampled at all?

Your definition is unusable, and seems to be contradictional to the usual one.

"A digital system is a data technology that uses discrete (discontinuous) values. By contrast, non-digital (or analog) systems use a continuous range of values to represent information." Thats all. No sampling need to be mentioned.

FM is a sine-ish wave clipped to look square after the limiter, but it is sampled as analogue.

What sampling do you refer to, and why do you say it's analog?

is voltage ladder ADC considered digital or analogue, sure it is an A-D converter, but instead of just one and zeros it can have values of 2 to 15.

I absolutely don't understand this. How could you ask if ADC is analog or digital? It's mixed! 2 to 15 ?!? What are you talking about?