# Fourier Transform and Sampling rate jitter

Started by July 5, 2007
```"Fourier Transform" transform the time domain data into frequency domain
information on the premise that the sampling rate is constant or in some
predictable manner. If the sampling clock jitter, it introduces noises
into the frequency domain information.

I would like to know, is there is formula whereby I can calculate the
amount of noise introduced, based on how much the clock jitter ?

```
```On Jul 5, 8:56 pm, "tonydeng" <deng301...@hotmail.com> wrote:
> "Fourier Transform" transform the time domain data into frequency domain
> information on the premise that the sampling rate is constant or in some
> predictable manner. If the sampling clock jitter, it introduces noises
> into the frequency domain information.
>
> I would like to know, is there is formula whereby I can calculate the
> amount of noise introduced, based on how much the clock jitter ?

Sure, there are many *approximation* methods for this
problem.  Look up "Leeson's formula" for one of them.

Julius

```
```On Jul 5, 6:56 pm, "tonydeng" <deng301...@hotmail.com> wrote:
> "Fourier Transform" transform the time domain data into frequency domain
> information on the premise that the sampling rate is constant or in some
> predictable manner. If the sampling clock jitter, it introduces noises
> into the frequency domain information.
>
> I would like to know, is there is formula whereby I can calculate the
> amount of noise introduced, based on how much the clock jitter ?

Try Analog Devices application notes AN-501 and AN-756

Dale B. Dalrymple
http://dbdimages.com

```
```On Thu, 05 Jul 2007 20:56:20 -0500, "tonydeng"
<deng301056@hotmail.com> wrote:

>"Fourier Transform" transform the time domain data into frequency domain
>information on the premise that the sampling rate is constant or in some
>predictable manner. If the sampling clock jitter, it introduces noises
>into the frequency domain information.
>
>I would like to know, is there is formula whereby I can calculate the
>amount of noise introduced, based on how much the clock jitter ?

Hey tonydeng,

beginning of your post.  That is just good
improves your chances of receiving help.

It would also help if your sentences were
grammitically correct (in English).  I don't
say that out of some sort of racism, but merely
because if you're going to ask a question in
some language (English in this case) it is
question if it is worded correctly.

Further, it would be helpful to you to tell us
what you have done to solve your problem.

tonydeng, what have YOU done, so far, to
solve YOUR problem?  Perhaps someone here
is willing to give YOU advice regarding
the method YOU used to solve YOUR problem.

And finally, you might receive more help if
you end your post with some sort of a
"Thank You" phrase letting the people here
know that you appreciate their help.

[-Rick-]
Cranky ol' fart.

```
```Rick Lyons wrote:
> On Thu, 05 Jul 2007 20:56:20 -0500, "tonydeng"
> <deng301056@hotmail.com> wrote:
>
> >"Fourier Transform" transform the time domain data into frequency domain
> >information on the premise that the sampling rate is constant or in some
> >predictable manner. If the sampling clock jitter, it introduces noises
> >into the frequency domain information.
> >
> >I would like to know, is there is formula whereby I can calculate the
> >amount of noise introduced, based on how much the clock jitter ?
>
> Hey tonydeng,
>
> beginning of your post.  That is just good
> Having respect for your DSP-superiors
> improves your chances of receiving help.
>
> It would also help if your sentences were
> grammitically correct (in English).  I don't
> say that out of some sort of racism, but merely
> because if you're going to ask a question in
> some language (English in this case) it is
> question if it is worded correctly.
>
> Further, it would be helpful to you to tell us
> what you have done to solve your problem.
>
> tonydeng, what have YOU done, so far, to
> solve YOUR problem?  Perhaps someone here
> is willing to give YOU advice regarding
> the method YOU used to solve YOUR problem.
>
> And finally, you might receive more help if
> you end your post with some sort of a
> "Thank You" phrase letting the people here
> know that you appreciate their help.
>
> [-Rick-]
> Cranky ol' fart.

Hi Rick,

I agree that showing some manners is good when posting questions and
answers.  However, using one of my postings as an example

it does not always get one all the help needed to clarify one's
understanding of the topic.

BR,
Phil
Cranky old fart in the making... at least if you ask my wife.

```
```On 11 Jul., 16:07, Phil <philguilleme...@alumni.uwaterloo.ca> wrote:
> Rick Lyons wrote:
> > On Thu, 05 Jul 2007 20:56:20 -0500, "tonydeng"
> > <deng301...@hotmail.com> wrote:
>
> > >"Fourier Transform" transform the time domain data into frequency domain
> > >information on the premise that the sampling rate is constant or in some
> > >predictable manner. If the sampling clock jitter, it introduces noises
> > >into the frequency domain information.
>
> > >I would like to know, is there is formula whereby I can calculate the
> > >amount of noise introduced, based on how much the clock jitter ?
>
> > Hey tonydeng,
>
> > beginning of your post.  That is just good
> > Having respect for your DSP-superiors
> > improves your chances of receiving help.
>
> > It would also help if your sentences were
> > grammitically correct (in English).  I don't
> > say that out of some sort of racism, but merely
> > because if you're going to ask a question in
> > some language (English in this case) it is
> > question if it is worded correctly.
>
> > Further, it would be helpful to you to tell us
> > what you have done to solve your problem.
>
> > tonydeng, what have YOU done, so far, to
> > solve YOUR problem?  Perhaps someone here
> > is willing to give YOU advice regarding
> > the method YOU used to solve YOUR problem.
>
> > And finally, you might receive more help if
> > you end your post with some sort of a
> > "Thank You" phrase letting the people here
> > know that you appreciate their help.
>
> > [-Rick-]
> > Cranky ol' fart.
>
> Hi Rick,
>
> I agree that showing some manners is good when posting questions and
> answers.  However, using one of my postings as an example
>
>
> it does not always get one all the help needed to clarify one's
> understanding of the topic.

The dynamics of usenet is sometimes unpredictable. Posts obeying full
netiquette get ignored, and vice versa. In the end, the responses you
get depend largely on whether you strike a nerve in the group of
people who are willing to spend time replying on usenet.

Courtesy and netiquette are only half the rent (as we say in
Switzerland :-). A question has to be interesting enough to be debated
but not too hard to exceed the working knowledge of the group members
and the possibilites of the usenet medium.

>
> BR,
> Phil
> Cranky old fart in the making... at least if you ask my wife.

There seem to be a couple of those around here :-).

Regards,
Andor

```
```On Wed, 11 Jul 2007 07:07:15 -0700, Phil
<philguillemette@alumni.uwaterloo.ca> wrote:

>
>Rick Lyons wrote:
>> On Thu, 05 Jul 2007 20:56:20 -0500, "tonydeng"
>> <deng301056@hotmail.com> wrote:
>>
>> >"Fourier Transform" transform the time domain data into frequency domain
>> >information on the premise that the sampling rate is constant or in some
>> >predictable manner. If the sampling clock jitter, it introduces noises
>> >into the frequency domain information.
>> >
>> >I would like to know, is there is formula whereby I can calculate the
>> >amount of noise introduced, based on how much the clock jitter ?
>>
>> Hey tonydeng,
>>
>> beginning of your post.  That is just good
>> Having respect for your DSP-superiors
>> improves your chances of receiving help.
>>
>> It would also help if your sentences were
>> grammitically correct (in English).  I don't
>> say that out of some sort of racism, but merely
>> because if you're going to ask a question in
>> some language (English in this case) it is
>> question if it is worded correctly.
>>
>> Further, it would be helpful to you to tell us
>> what you have done to solve your problem.
>>
>> tonydeng, what have YOU done, so far, to
>> solve YOUR problem?  Perhaps someone here
>> is willing to give YOU advice regarding
>> the method YOU used to solve YOUR problem.
>>
>> And finally, you might receive more help if
>> you end your post with some sort of a
>> "Thank You" phrase letting the people here
>> know that you appreciate their help.
>>
>> [-Rick-]
>> Cranky ol' fart.
>
>Hi Rick,
>
>I agree that showing some manners is good when posting questions and
>answers.  However, using one of my postings as an example
>
>
>it does not always get one all the help needed to clarify one's
>understanding of the topic.
>
>BR,
>Phil
>Cranky old fart in the making... at least if you ask my wife.

Hi Phil,
Welcome To The Club.

Yes, it is sometimes mysterious why some
posts receive replies and other posts do
not.  I certainly am not sure why this is
so.

My only point was that "clarity and good manners"
improve a poster's chances of success.

See Ya',
[-Rick-]

```