1. Home
  2. Electronics Design
  3. Definition of Linearity

Definition of Linearity

I have a specification for an amplifier design that says "0.25% linearity".

I can't seem to lay my hands on a precise definition of what that means.

Likewise... How to calculate?

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

formatting link
| 1962 | America: Land of the Free, Because of the Brave

Reply to
Jim Thompson
Loading thread data ...

Better ask the customer. (Even if they are not correct in their definition, it is their definition that you need to know.) Chris

Reply to
Chris Jones

Probably peak deviation from best straight-line fit, as a percentage of full-scale swing. Most people would use half of rail-rail output swing (ie, peak, not p-p) as the denominator.

John

Reply to
John Larkin

The data converter people have some measures of non-linearity.

See:

formatting link

formatting link

Maybe your customer is thinking of something along these lines.

Reply to
The Phantom

That's sort of what I was musing. Now to implement it in PSpice.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

Regardless, nice links... thanks.

Reply to
Spurious Response

Thanks!

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

Do marketing types know how to divide?

John

Reply to
John Larkin

The max. deviation from the straight line is a very complex concept. Probably they ment the THD of 0.25%

Vladimir Vassilevsky

DSP and Mixed Signal Design Consultant

formatting link

Reply to
Vladimir Vassilevsky

Except for marketing types.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany

Shouldn't one question be 'what type of amp is this?' Like audio amp, rf amp, etc.?

Reply to
Spurious Response

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

wouldnt that just translate to 0.25% voltage distortion ? I assume that 0.25% is a linearity , otherwise it would be a rather poor amplifier.

Colin =^.^=

Reply to
colin

Ya mean something like 99.75% distortion? ;-)

Reply to
PhattyMo

It relates to well known definition that says "You _can_ draw a straight line through any three points if it is thick enough".

HTH

Stanislaw

Reply to
Stanislaw Flatto

The very word almost invariably refers to A/D errors these days, and typically specifies 1/2LSB maximum error due to all amplifier characteristics: offsets, gain errors, rolloff. The 0.25% would be approximately 1/2LSB for an 8-bit.

Reply to
Fred Bloggs

Vladimir Vassilevsky a écrit :

...which then is the rms deviation from straight line. Not a much simpler concept I'm afraid :-)

--
Thanks,
Fred.
Reply to
Fred Bartoli

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Jim, is that the spec for a ramp generator, or a scanning amplifier ?

Jure Z.

Reply to
Jure Newsgroups

"Fred Bartoli"

** The world recognised, published authorities on this topic are messrs:

Dave Dee, Dozy, Beaky, Mick and Titch.

Their seminal 1966s work on "linearity " was mischievously entitled " Bend It ".

Not another word needs to be said .......

........ Phil

Reply to
Phil Allison

Sno-o-o-ort ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

It's an amplifier with less than 10KHz bandwidth (to get quick settling), gain of 300, but it's essentially a DC signal.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.