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I know it's associated with digital overload power, but
I'm looking for a more precise definition; something like:

0 dBOV = 10*log P1/Pref, 

where Pref is the maximum RMS SINEWAVE power possible. The
basic question is this: is it RMS power or peak power, and 
if it is RMS power, for what type of waveform?
-- 
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
r...@sonyericsson.com, 919-472-1124

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Randy Yates <r...@sonyericsson.com> writes:
> 0 dBOV = 10*log P1/Pref, 

Sorry, that should read

  dBOV = 10*log P1/Pref, 

-- 
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
r...@sonyericsson.com, 919-472-1124

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Randy Yates wrote:

> I know it's associated with digital overload power, but
> I'm looking for a more precise definition; something like:
> 
> 0 dBOV = 10*log P1/Pref, 
> 
> where Pref is the maximum RMS SINEWAVE power possible. The
> basic question is this: is it RMS power or peak power, and 
> if it is RMS power, for what type of waveform?

No answer, just another question. dBov is relative to system overload,
but I see it quoted as large positive numbers. Is there an implicit
minus sign?

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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Jerry Avins <j...@ieee.org> writes:

> Randy Yates wrote:
>
>> I know it's associated with digital overload power, but
>> I'm looking for a more precise definition; something like:
>> 0 dBOV = 10*log P1/Pref, where Pref is the maximum RMS SINEWAVE
>> power possible. The
>> basic question is this: is it RMS power or peak power, and if it is
>> RMS power, for what type of waveform?
>
> No answer, just another question. dBov is relative to system overload,
> but I see it quoted as large positive numbers. Is there an implicit
> minus sign?

Not that I know of, Jerry. I've seen it as a negative number.
-- 
%  Randy Yates                  % "Maybe one day I'll feel her cold embrace,
%% Fuquay-Varina, NC            %                    and kiss her interface, 
%%% 919-577-9882                %            til then, I'll leave her alone."
%%%% <y...@ieee.org>           %        'Yours Truly, 2095', *Time*, ELO   
http://home.earthlink.net/~yatescr

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Randy Yates wrote:

> Jerry Avins <j...@ieee.org> writes:
> 
> 
>>Randy Yates wrote:
>>
>>
>>>I know it's associated with digital overload power, but
>>>I'm looking for a more precise definition; something like:
>>>0 dBOV = 10*log P1/Pref, where Pref is the maximum RMS SINEWAVE
>>>power possible. The
>>>basic question is this: is it RMS power or peak power, and if it is
>>>RMS power, for what type of waveform?
>>
>>No answer, just another question. dBov is relative to system overload,
>>but I see it quoted as large positive numbers. Is there an implicit
>>minus sign?
> 
> 
> Not that I know of, Jerry. I've seen it as a negative number.

Thanks. A quick look with Google confirms that. I guess I generalized
from a very small sample.

If I wanted a measure relative to overload, I'd define overload first.
For DACs and ADCs, it's peak voltage. It seems reasonable (but hardly
proof) that dBov is defined that way.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

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Jerry Avins <j...@ieee.org> writes:
> [...]
> If I wanted a measure relative to overload, I'd define overload first.
> For DACs and ADCs, it's peak voltage. It seems reasonable (but hardly
> proof) that dBov is defined that way.

I would say it's clear what an overload is (something exceeding full-scale),
but since there are a number of ways to specify it. The question is then
"Which way was it specified" (e.g., "full-scale RMS sine wave" or "full-scale
square wave power" are two most-probable methods).

By the way, an SEMC colleague believes it is the full-scale RMS sinewave
power method. 
-- 
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
r...@sonyericsson.com, 919-472-1124

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Randy Yates wrote:

> Jerry Avins <j...@ieee.org> writes:
> 
>>[...]
>>If I wanted a measure relative to overload, I'd define overload first.
>>For DACs and ADCs, it's peak voltage. It seems reasonable (but hardly
>>proof) that dBov is defined that way.
> 
> 
> I would say it's clear what an overload is (something exceeding full-scale),
> but since there are a number of ways to specify it. The question is then
> "Which way was it specified" (e.g., "full-scale RMS sine wave" or "full-scale
> square wave power" are two most-probable methods).
> 
> By the way, an SEMC colleague believes it is the full-scale RMS sinewave
> power method. 

Even analog amplifiers, as long as they have stiff power supplies and
are not too heavily loaded, clip at some particular voltage. DACs clip
at MAX_Int, etc. A*[sin(wt) + sin(3wt)] and A*[sin(wt) - sin(3wt)] have
precisely the same RMS power, but the second will pass undistorted
through a system that clips the first. That said, RMS sinewave power may
indeed be the standard. I never got very far by taking for granted that
the world is rational.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

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Hi,

I don't know about dBov, but perhaps it is similar to dBO, used in PCM
(i.e. A-law and u-Law) telecoms. That is defined as 8 specific samples
which will produce a 1kHz sine wave that is considered 0dBO. The clip
point turns about to be about +3.14dBO for a sine wave. I would think
it likely that dBov would be defined in a similar sine wave manner,
but with the wave being considered 0dBov just below clip. Square wave
are also a possibility, I guess, but engineers have a deep love of
sine waves. :-)

Regards,
Steve


Randy Yates <r...@sonyericsson.com> wrote in message
news:<x...@usrts005.corpusers.net>...
> Jerry Avins <j...@ieee.org> writes:
> > [...]
> > If I wanted a measure relative to overload, I'd define overload first.
> > For DACs and ADCs, it's peak voltage. It seems reasonable (but hardly
> > proof) that dBov is defined that way.
> 
> I would say it's clear what an overload is (something exceeding full-scale),
> but since there are a number of ways to specify it. The question is then
> "Which way was it specified" (e.g., "full-scale RMS sine wave" or "full-scale
> square wave power" are two most-probable methods).
> 
> By the way, an SEMC colleague believes it is the full-scale RMS sinewave
> power method.

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On Tue, 11 May 2004 13:55:40 -0400, Jerry Avins <j...@ieee.org> wrote:


>A*[sin(wt) + sin(3wt)] and A*[sin(wt) - sin(3wt)] have
>precisely the same RMS power

I could have sworn they have the same *average* power.

Regards,
Allan.

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Allan Herriman wrote:

> On Tue, 11 May 2004 13:55:40 -0400, Jerry Avins <j...@ieee.org> wrote:
> 
> 
> 
>>A*[sin(wt) + sin(3wt)] and A*[sin(wt) - sin(3wt)] have
>>precisely the same RMS power
> 
> 
> I could have sworn they have the same *average* power.
> 
> Regards,
> Allan.

The total RMS power is the sum of the components' individual RMS powers.
A component's RMS power is unchanged by changing its sign. I haven't
(and won't) compute average power, but I guess you're right. I can see
by inspection that the ratio of peak powers is about 5:8.

How do we disagree?

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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