Electronics > Beginners
Frequency error in scientific notation
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tooki:

--- Quote from: tomato on February 02, 2019, 07:15:06 pm ---Commas, decimals, and spacers are all acceptable, but the U.S. is in the minority using the decimal.

(Re: 22nd CGPM, section 10)

https://www.bipm.org/jsp/en/ListCGPMResolution.jsp?CGPM=22

--- End quote ---
Huh? That text in no way suggests that the point as the decimal is the minority. (The decimal is the separator, whether it’s a comma or point.)
Benta:

--- Quote from: KE5FX on February 02, 2019, 06:56:56 pm ---
Nope.  Usually it's us US-ians who change things for no good reason, but in this case it's the Europeans.  I actually looked into this at one point, when I was curious to learn who thought it was a good idea to use the comma as a decimal point.  It's a relatively modern change.  What I wasn't able to discover was the reason behind the change.

This isn't a question of some old farts from the 1960s who refuse to switch from cycles per second to Hertz.  It's literally the sort of thing that shows up in case studies after a bunch of people get killed.  Unnecessary changes like this need to be fought, and fought hard.

--- End quote ---

I'm not certain what you mean by this. The decimal comma has been used at least since the 19th century in continental Europe, but Britain favoured the point.
You reference to "modern change" must refer to computer technology, where the comma at some point was used to delimit lists, options and variables and as such could cause problems with numbers.

That being said, I have two preferred options for presenting large numbers:

10.000 000 000 5 (US/UK) or 10,000 000 000 5 (EU). This one is not my 1st favourite, as it can present problems in formating.

10.000'000'000'5 (US/UK) or 10,000'000'000'5 (EU). I like it,as it's practically impossible to misinterpret and easy to read.

In both cases, adding two zeros at the end would add to aesthetics.

But everyone has his/her own style, I find clarity most important, speaking as an engineer.
IanB:

--- Quote from: tkamiya on February 02, 2019, 04:09:18 pm ---Say output is 10MHz, and reading is 10.000,000,000,5Mhz, what is the error rate in scientific notation? 

Is it 5x10^11 or 5x10^12?
--- End quote ---

Your specified frequency is 10 MHz, and your reading is 10.000 000 000 5 MHz.

Therefore the absolute error is (10.000 000 000 5 - 10) MHz = +0.000 000 000 5 MHz

In scientific notation this is +5 x 10-10 MHz (you have to move the decimal 10 places to the left of the 5 to recover the original value).

The relative error is (+5 x 10-10) MHz / 10 MHz = +5 x 10-11 (no units).
IanB:

--- Quote from: Benta on February 02, 2019, 07:43:55 pm ---But everyone has his/her own style, I find clarity most important, speaking as an engineer.

--- End quote ---

I believe there is an ISO standard for writing values in scientific and technical communications. Among other things I believe it prefers the use of "." as a decimal separator, that groups of three digits should be separated by a space, and that there should be a space between the value and the unit of measure (e.g. write 5 V not 5V).
Benta:

--- Quote from: tooki on February 02, 2019, 07:26:10 pm ---
--- Quote from: tomato on February 02, 2019, 07:15:06 pm ---Commas, decimals, and spacers are all acceptable, but the U.S. is in the minority using the decimal.

(Re: 22nd CGPM, section 10)

https://www.bipm.org/jsp/en/ListCGPMResolution.jsp?CGPM=22

--- End quote ---
Huh? That text in no way suggests that the point as the decimal is the minority. (The decimal is the separator, whether it’s a comma or point.)

--- End quote ---

Actually, that link is quite good, as it defines a rule that can be understood by anyone:
Texts in English use decimal point.
Texts in French, German, Russian (and other continental European languages) use decimal comma.

What happens in other languages is apparently undefined.
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