>
> I did not mean to engender a personal war...
>
> just to clear up some points, I know the physical principles my sensor is
> based on, the voltage produced by the piezoelectric crystal is properly
> processed and calibrated, so that what we get can be used to measure
> quasi-static and dynamic tensile and compression forces.
>
> Second point: our application works fine already at the sampling frequency
> we are using (that is in total accordance with what Glen wrote in one of
> his posts). However we were interested in reducing the sampling frequency,
> if we could still get an accurate estimate of the integral in a easy way.
The piezo devices have a response that in the frequency domain looks like a
triangle. The scale of that triangle will depend on the shape/size of the piezo
material. Ideally you will be sampling at a rate so that you are dealing with
frequencies that are in the section of the frequency response that is a rising
straight line.
Nobody can give you a good answer to your question about sample rates and
frequency response without knowing the response of your device.
If you reduce the sample rate. Do you get a different result? That should be
easy to determine from the data. What does the manufacturer recommend?
>
> Third point: we do need an exact estimation of the FORCE integral, since,
> as sharply deuced by Clay, we have a strong force produced by a jet of
> fluid that exists for a brief period of time. For physical reasons I am not
> going to explain here, we need to calculate the force integral by
> integrating with respect of time for different distances between the sensor
> and the jet, then differentiate with respect of the distance.
You originally said that this is what you are doing :
( sum(Xi*delta(x))).
That represents just summing a block of samples and multiplying by a scale
factor. No?
Are you doing this operation just once on the entire set of data or is this a
moving average that produces a new set of samples?
>
> So for what I read, illywhacker was the one who better focused the problem
> at hand (my falult was surely that I did not give all the details!).
>
> Alex
Reply by Alex_001●February 27, 20092009-02-27
I did not mean to engender a personal war...
just to clear up some points, I know the physical principles my sensor is
based on, the voltage produced by the piezoelectric crystal is properly
processed and calibrated, so that what we get can be used to measure
quasi-static and dynamic tensile and compression forces.
Second point: our application works fine already at the sampling frequency
we are using (that is in total accordance with what Glen wrote in one of
his posts). However we were interested in reducing the sampling frequency,
if we could still get an accurate estimate of the integral in a easy way.
Third point: we do need an exact estimation of the FORCE integral, since,
as sharply deuced by Clay, we have a strong force produced by a jet of
fluid that exists for a brief period of time. For physical reasons I am not
going to explain here, we need to calculate the force integral by
integrating with respect of time for different distances between the sensor
and the jet, then differentiate with respect of the distance.
So for what I read, illywhacker was the one who better focused the problem
at hand (my falult was surely that I did not give all the details!).
Alex
Reply by illywhacker●February 27, 20092009-02-27
On Feb 27, 2:03�am, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
wrote:
> jim wrote:
>
> Something reminds me of Gary Cain and Bob Sokolich...
>
> VLV
I am glad someone is getting something out of it, if only unpleasant
associations.
illywhacker;
Reply by illywhacker●February 27, 20092009-02-27
On Feb 27, 1:56�am, jim <".sjedgingN0sp"@m...@mwt.net> wrote:
> illywhacker wrote:
>
> > There is a saying, Jim: "never attribute to malice that which is
> > adequately explained by stupidity". I am following its advice.
>
> � � � � Haven't you been operating from the beginning on the assumption that every
> message to which you reply is malicious or stupid?
Um, Jim - the saying *distinguishes* between malicious and stupid and
chooses the latter over the former. It is only eleven words Jim,
although admittedly two of them have four syllables and one has three.
Is that the problem with understanding it? �
> Why would I have wasted
> effort on constructing misrepresentations? �Wouldn't it be just easier to say
> something stupid since it is obvious it will do just as well?
Um, Jim - you *did* say something stupid.
illywhacker;
Reply by Vladimir Vassilevsky●February 26, 20092009-02-26
jim wrote:
>
> illywhacker wrote:
>
>
>>There is a saying, Jim: "never attribute to malice that which is
>>adequately explained by stupidity". I am following its advice.
>
>
> Haven't you been operating from the beginning on the assumption that every
> message to which you reply is malicious or stupid? Why would I have wasted
> effort on constructing misrepresentations? Wouldn't it be just easier to say
> something stupid since it is obvious it will do just as well?
Something reminds me of Gary Cain and Bob Sokolich...
VLV
Reply by jim●February 26, 20092009-02-26
illywhacker wrote:
>
> There is a saying, Jim: "never attribute to malice that which is
> adequately explained by stupidity". I am following its advice.
Haven't you been operating from the beginning on the assumption that every
message to which you reply is malicious or stupid? Why would I have wasted
effort on constructing misrepresentations? Wouldn't it be just easier to say
something stupid since it is obvious it will do just as well?
-jim
Reply by illywhacker●February 26, 20092009-02-26
On Feb 26, 8:15�pm, jim <".sjedgingN0sp"@m...@mwt.net> wrote:
> illywhacker wrote:
>
> > On Feb 26, 6:00 pm, jim <".sjedgingN0sp"@m...@mwt.net> wrote:
> > > illywhacker wrote:
>
> > > > No, Jim. Your reading age is really down there with things like
> > > > 'number of fingers on one hand' isn't it?
>
> > > > "He doesn't want the integral of force. Force is just an abstract
> > > > concept here so is integration. Movement in space is what produces a
> > > > voltage."
>
> > > Yes , I said that because some idiot said "He wants the integral of Force". So I
> > > says "no he doesn't". He says "yes he does" I says "no he doesn't" He says "yes
> > > he does" ......
>
> > No, Jim. I said 'Since the OP mentions "force", I assume it is the
> > latter rather than the former. Did I miss something?', and you said:
>
> > "No you didn't miss that. I was thinking he said acceleration but you
> > are correct he said force"
>
> > rather than the chain of contradictions you just asserted.
>
> If I say this discussion has been nothing more than a chain of contradictions
> how is that not an accurate assessment?
>
>
>
> > > � �Now what misrepresentation did I make?
>
> > I just gave you one.
>
> How does characterizing the discussion as a back and forth of �" Yes he did. No
> he didn't. Yes he did. No he didn't. Yes he did. No he didn't..... " constitute
> a misrepresentation? If that is not correct, what is?
>
> > Here's another: until this post, you have not
> > asked me a question,
>
> Really? If I were to ask the question now, would I get an answer?
>
> > apart from a few hysterical rhetorical
> > screeches, yet you assert that you asked me what misrepresentation
> > you made:
>
> �OK if you insist I have not asked let me ask now, Did you or did you not say I
> was making misrepresentations? And if the answer is yes, what were those
> misrepresentations?
There is a saying, Jim: "never attribute to malice that which is
adequately explained by stupidity". I am following its advice.
illywhacker;
Reply by jim●February 26, 20092009-02-26
illywhacker wrote:
>
> On Feb 26, 6:00 pm, jim <".sjedgingN0sp"@m...@mwt.net> wrote:
> > illywhacker wrote:
>
> > > No, Jim. Your reading age is really down there with things like
> > > 'number of fingers on one hand' isn't it?
>
> > > "He doesn't want the integral of force. Force is just an abstract
> > > concept here so is integration. Movement in space is what produces a
> > > voltage."
> >
> > Yes , I said that because some idiot said "He wants the integral of Force". So I
> > says "no he doesn't". He says "yes he does" I says "no he doesn't" He says "yes
> > he does" ......
>
> No, Jim. I said 'Since the OP mentions "force", I assume it is the
> latter rather than the former. Did I miss something?', and you said:
>
> "No you didn't miss that. I was thinking he said acceleration but you
> are correct he said force"
>
> rather than the chain of contradictions you just asserted.
If I say this discussion has been nothing more than a chain of contradictions
how is that not an accurate assessment?
>
> > Now what misrepresentation did I make?
>
> I just gave you one.
How does characterizing the discussion as a back and forth of " Yes he did. No
he didn't. Yes he did. No he didn't. Yes he did. No he didn't..... " constitute
a misrepresentation? If that is not correct, what is?
> Here's another: until this post, you have not
> asked me a question,
Really? If I were to ask the question now, would I get an answer?
> apart from a few hysterical rhetorical
> screeches, yet you assert that you asked me what misrepresentation
> you made:
OK if you insist I have not asked let me ask now, Did you or did you not say I
was making misrepresentations? And if the answer is yes, what were those
misrepresentations?
-jim
Reply by illywhacker●February 26, 20092009-02-26
On Feb 26, 6:00 pm, jim <".sjedgingN0sp"@m...@mwt.net> wrote:
> illywhacker wrote:
> > No, Jim. Your reading age is really down there with things like
> > 'number of fingers on one hand' isn't it?
> > "He doesn't want the integral of force. Force is just an abstract
> > concept here so is integration. Movement in space is what produces a
> > voltage."
>
> Yes , I said that because some idiot said "He wants the integral of Force". So I
> says "no he doesn't". He says "yes he does" I says "no he doesn't" He says "yes
> he does" ......
No, Jim. I said 'Since the OP mentions "force", I assume it is the
latter rather than the former. Did I miss something?', and you said:
"No you didn't miss that. I was thinking he said acceleration but you
are correct he said force"
rather than the chain of contradictions you just asserted.
> Now what misrepresentation did I make?
I just gave you one. Here's another: until this post, you have not
asked me a question, apart from a few hysterical rhetorical
screeches, yet you assert that you asked me what misrepresentation
you made:
"I asked you a simple question. What misrepresentation did I make?"
Look yourself for the others.
illywhacker;
Reply by jim●February 26, 20092009-02-26
illywhacker wrote:
>
> On Feb 26, 4:41 pm, jim <".sjedgingN0sp"@m...@mwt.net> wrote:
>
> > I see. What you are calling misrepresentation on my part appears to be really
> > misinterpretation on your part. Calling this a "pissing contest" was not
> > intended as an accusation that you had used "bad words".
>
> No, Jim. Your reading age is really down there with things like
> 'number of fingers on one hand' isn't it?
I asked you a simple question. What misrepresentation did I make? Do you know
what a question is?
> You resorted to bad words,
> Jim, perhaps because they make your 'buddies' guffaw. It's a
> different story with adults though.
>
OK. Let's suppose that is true. You still haven't explained what
misrepresentation you think I made.
>
> "He doesn't want the integral of force. Force is just an abstract
> concept here so is integration. Movement in space is what produces a
> voltage."
>
Yes , I said that because some idiot said "He wants the integral of Force". So I
says "no he doesn't". He says "yes he does" I says "no he doesn't" He says "yes
he does" ......
See that is how a pissing contest works. Now what misrepresentation did I make?
-jim