"Decimals" word in binary space

Im looking for an equivalent word for "decimal" in a binary number. The 
"deci" says it's all about base 10 numbers, but I miss an official term for 
the 1/(2^n) digits. I'm using "binimals"  in lack of a better word.
Also, is there a binary world equivalent for the "decimal" point?

On Wednesday, August 15, 2012 6:35:55 AM UTC-5, Morten Leikvoll wrote:
> Im looking for an equivalent word for "decimal" in a binary number. The "=
deci" says it's all about base 10 numbers, but I miss an official term for =
the 1/(2^n) digits. I'm using "binimals" in lack of a better word. Also, is=
 there a binary world equivalent for the "decimal" point?

I don't believe "decimals" is correctly used to refer to decimal digits. Ma=
ybe Decimal places... Binary digits (or binary bits or just bits) and binar=
y point are the accepted terms you seek.

Andy

>I don't believe "decimals" is correctly used to refer to decimal digits. 
>Maybe Decimal places... Binary digits (or binary bits or just bits) and 
>binary point are the accepted terms you seek.

The examples shown in http://www.merriam-webster.com/dictionary/decimals 
says

"The number 67.398 is a decimal. It is equal to the whole number 67 plus the 
decimal.398.
Seven-tenths written as a decimal is.7. Seven-tenths written as a fraction 
is {frac7.
The decimal.2 is equal to the fraction {frac2."

(never seen the {frac notation before though)
There is the integer, or leading digits part. I guess the rest is called 
non-integer part, but it sounds a bit clumsy. Is there another word? In my 
native language the word most similar to decimal is used for the non integer 
part only. And if you look in the cell formatting of a spread sheet, the 
term "decimal places" refer to the # of digits to the right of the dot.
I guess I could call those digits the modulo1 part of the value as well. 
Those terms works with any number base, but also clumsy.

I would like an easy way to express a reference to the N'th digit of either 
the integer or the modulo1 part and I'm not really happy with my current 
options..

"Morten Leikvoll" <mleikvol@yahoo.nospam> wrote in message 
news:ssWdnbZrfZ4GFLbNnZ2dnUVZ8vKdnZ2d@lyse.net...
> Im looking for an equivalent word for "decimal" in a binary number. The 
> "deci" says it's all about base 10 numbers, but I miss an official term 
> for the 1/(2^n) digits. I'm using "binimals"  in lack of a better word.
> Also, is there a binary world equivalent for the "decimal" point?
>

Do you mean hexadecimal where 4bit nibbles are used to describe each decade? 

Morten Leikvoll <mleikvol@yahoo.nospam> wrote:

> Im looking for an equivalent word for "decimal" in a binary number. 
> The "deci" says it's all about base 10 numbers, but I miss an 
> official term for the 1/(2^n) digits. I'm using "binimals"  
> in lack of a better word.

It seems that decimal is used for both the base and for numbers,
especially fractional numbers, written in it. Also for binary.

Exactly why, I don't know.

More specifically, it seems that people sometimes use the word
"decimal" as short for "decimal fraction" or digits after the 
decimal point.

> Also, is there a binary world equivalent for the "decimal" point?

There is a binary point, also octal point and hexadecimal point 
if you happen to be in one of those radices, and generic radix
point.

Metric fractions are decimal for obvious reasons, but why are
fractions of an inch usually binary? (Though written as fractions
with powers of two in the denominator.)

-- glen

Morten Leikvoll wrote:

> Im looking for an equivalent word for "decimal" in a binary number. The
> "deci" says it's all about base 10 numbers, but I miss an official term
> for
> the 1/(2^n) digits. I'm using "binimals"  in lack of a better word.
> Also, is there a binary world equivalent for the "decimal" point?
The correct term, I think, is decimal fraction, so the equivalent
would be binary fraction.

Jon

Jon Elson <jmelson@wustl.edu> wrote:

(snip)

> The correct term, I think, is decimal fraction, so the equivalent
> would be binary fraction.

Yes, often shortened to decimal.

Reminds me, that I never understood how "application program" got
reduced to "application" and then "app." Doesn't sound right to me.

-- glen

Morten Leikvoll wrote:
>
> There is the integer, or leading digits part. I guess the rest is called
> non-integer part, but it sounds a bit clumsy. Is there another word?
> <snip>
>
> I would like an easy way to express a reference to the N'th digit of eith=
er
> the integer or the modulo1 part and I'm not really happy with my current
> options..

The notation I'm familiar with refers to the various portions of a
two's complement signed fractional binary number as follows [Ref 1]:

siii.ffff
s : sign bit
i : integer bit
. : binary point
f : fractional bit

The individual bits are then referred to by their binary weighting,
2^N, where N can be negative for fractional formats.

For the above fraction
2^2 =3D most significant integer bit
2^0 =3D least significant integer bit
2^-1 =3D most significant fractional bit

The VHDL fixed point package [Ref 3] indexes fractional numbers
by using N directly in index and range expressions.

- Brian

References:

[Ref 1] "Fractional and Integer Arithmetic using the DSP56000 Family
of General-Purpose Digital Signal Processors", APR3/D Rev. 1
http://cache.freescale.com/files/dsp/doc/app_note/APR3.pdf

[Ref 2] "Fixed-Point Arithmetic: An Introduction", Randy Yates
http://personal.atl.bellsouth.net/y/a/yatesc/fp.pdf

[Ref 3] "Fixed Point Package User=92s Guide", David Bishop
http://www.vhdl.org/fphdl/Fixed_ug.pdf

>The notation I'm familiar with refers to the various portions of a
>two's complement signed fractional binary number as follows [Ref 1]:
>siii.ffff
>s : sign bit
>i : integer bit
>. : binary point
>f : fractional bit

Fair enough, but initially why cant we just adopt the minus sign for 
negative numbers when writing. Ok, the machine implementation of it needs 
the sign bit, but brain-mapping arithmetics with base10 to base2 (or any 
base) becomes more complicated if you do it before implementation imho.

>The individual bits are then referred to by their binary weighting,
>2^N, where N can be negative for fractional formats.
>For the above fraction
>2^2 = most significant integer bit
>2^0 = least significant integer bit
>2^-1 = most significant fractional bit

so to keep the base10 terms, the 2^0'th bit would be the first integer 
bit/digit, 2^1 would be the second and so on..
For the fraction, 2^(-1) would be the first fractional bit/digit, 2^(-2) the 
second and so on.
Now, I do miss a compact word for "integer bit" and "fractional bit".

>The VHDL fixed point package [Ref 3] indexes fractional numbers
>by using N directly in index and range expressions.

I had to give up using fractional types cause I was not satisfied with the 
packages. I ended up using logic vectors and keeping track on the fractional 
part myself. At least then I could blame myself if something went wrong..

This link also suggests that sometimes "decimals" are used for the 
fractional part only : http://www.thefreedictionary.com/decimal
I would claim the word is a bit washed out if the definition is not clear.