Derivative of signal

On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:

>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>>>
>>>> could somebody give me an advice? At the moment I am solving
>>>> interesting problem. I have been using SW PLL with SOGI circuit to
>>>> obtain grid frequency
>>
>>
>>>
>>> You could design a simple control loop with an integrator in the
>>> feedback path. This will give you band-limited differentiation ie a
>>> slope of 6dB/octave.
>>
>> Good point. As the OP is using PLL, the output of phase detector is
>> derivative of frequency.
>>
>> VLV
>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
> > On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
> >> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
> >>>
> >>> could somebody give me an advice? At the moment I am solving
> >>> interesting problem. I have been using SW PLL with SOGI circuit to
> >>> obtain grid frequency
> >
> >
> >>
> >> You could design a simple control loop with an integrator in the
> >> feedback path. This will give you band-limited differentiation ie a
> >> slope of 6dB/octave.
> >
> > Good point. As the OP is using PLL, the output of phase detector is
> > derivative of frequency.
> >
> > VLV
>
>It still needs filtering.
>
>Digital approximations to derivatives come in many forms. The simplest 
>and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications, 
>y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of 
>latency. Rick Lyons improves on that with two more delay terms and the 
>corresponding extra latency. I'm not certain that I'm at liberty to 
>provide more details. I expect that he will.
>
>Jerry

Good to see you posting again, Jerry.   A few of us were wondering
where you were.   I hope you're well.


Eric Jacobsen
Anchor Hill Communications
http://www.anchorhill.com

On Sunday, June 9, 2013 4:35:17 PM UTC+12, Eric Jacobsen wrote:
> On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:
> 
> 
> 
> >On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
> 
> >> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
> 
> >>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
> 
> >>>>
> 
> >>>> could somebody give me an advice? At the moment I am solving
> 
> >>>> interesting problem. I have been using SW PLL with SOGI circuit to
> 
> >>>> obtain grid frequency
> 
> >>
> 
> >>
> 
> >>>
> 
> >>> You could design a simple control loop with an integrator in the
> 
> >>> feedback path. This will give you band-limited differentiation ie a
> 
> >>> slope of 6dB/octave.
> 
> >>
> 
> >> Good point. As the OP is using PLL, the output of phase detector is
> 
> >> derivative of frequency.
> 
> >>
> 
> >> VLV
> 
> >On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
> 
> > > On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
> 
> > >> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
> 
> > >>>
> 
> > >>> could somebody give me an advice? At the moment I am solving
> 
> > >>> interesting problem. I have been using SW PLL with SOGI circuit to
> 
> > >>> obtain grid frequency
> 
> > >
> 
> > >
> 
> > >>
> 
> > >> You could design a simple control loop with an integrator in the
> 
> > >> feedback path. This will give you band-limited differentiation ie a
> 
> > >> slope of 6dB/octave.
> 
> > >
> 
> > > Good point. As the OP is using PLL, the output of phase detector is
> 
> > > derivative of frequency.
> 
> > >
> 
> > > VLV
> 
> >
> 
> >It still needs filtering.
> 
> >
> 
> >Digital approximations to derivatives come in many forms. The simplest 
> 
> >and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications, 
> 
> >y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of 
> 
> >latency. Rick Lyons improves on that with two more delay terms and the 
> 
> >corresponding extra latency. I'm not certain that I'm at liberty to 
> 
> >provide more details. I expect that he will.
> 
> >
> 
> >Jerry
> 
> 
> 
> Good to see you posting again, Jerry.   A few of us were wondering
> 
> where you were.   I hope you're well.
> 
> 
> 
> 
> 
> Eric Jacobsen
> 
> Anchor Hill Communications
> 
> http://www.anchorhill.com

Haven't tried this but

int(k)=int(k-1)+gain*out(k-1)
out(k)=input(k)-int(k)


Where input and output are the input and output arrays

integrator in feedback path and gain is a small positive number
which you can calculate. Should give something like

s*tau/(1+s*tau)

On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:

>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>>>
>>>> could somebody give me an advice? At the moment I am solving
>>>> interesting problem. I have been using SW PLL with SOGI circuit to
>>>> obtain grid frequency
>>
>>
>>>
>>> You could design a simple control loop with an integrator in the
>>> feedback path. This will give you band-limited differentiation ie a
>>> slope of 6dB/octave.
>>
>> Good point. As the OP is using PLL, the output of phase detector is
>> derivative of frequency.
>>
>> VLV
>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
> > On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
> >> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
> >>>
> >>> could somebody give me an advice? At the moment I am solving
> >>> interesting problem. I have been using SW PLL with SOGI circuit to
> >>> obtain grid frequency
> >
> >
> >>
> >> You could design a simple control loop with an integrator in the
> >> feedback path. This will give you band-limited differentiation ie a
> >> slope of 6dB/octave.
> >
> > Good point. As the OP is using PLL, the output of phase detector is
> > derivative of frequency.
> >
> > VLV
>
>It still needs filtering.
>
>Digital approximations to derivatives come in many forms. The simplest 
>and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications, 
>y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of 
>latency. Rick Lyons improves on that with two more delay terms and the 
>corresponding extra latency. I'm not certain that I'm at liberty to 
>provide more details. I expect that he will.
>
>Jerry

Hi Jerry,
  If you're referring to the differentiator that 
I think you are, then it's described in detail 
at:

http://www.dsprelated.com/showarticle/35.php

See Ya',
[-Rick-]
No. 6: "What do you want?"
No. 2: "Information."
No. 6: "Who are you?"
No. 2: "I am the new No. 2."
No. 6: "Who is No. 1?"
No. 2: "You are No. 6."
No. 6: "I am not a number. I am a free man!"

>On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:
>
>>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>>>>
>>>>> could somebody give me an advice? At the moment I am solving
>>>>> interesting problem. I have been using SW PLL with SOGI circuit to
>>>>> obtain grid frequency
>>>
>>>
>>>>
>>>> You could design a simple control loop with an integrator in the
>>>> feedback path. This will give you band-limited differentiation ie a
>>>> slope of 6dB/octave.
>>>
>>> Good point. As the OP is using PLL, the output of phase detector is
>>> derivative of frequency.
>>>
>>> VLV
>>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>> > On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>> >> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>> >>>
>> >>> could somebody give me an advice? At the moment I am solving
>> >>> interesting problem. I have been using SW PLL with SOGI circuit to
>> >>> obtain grid frequency
>> >
>> >
>> >>
>> >> You could design a simple control loop with an integrator in the
>> >> feedback path. This will give you band-limited differentiation ie a
>> >> slope of 6dB/octave.
>> >
>> > Good point. As the OP is using PLL, the output of phase detector is
>> > derivative of frequency.
>> >
>> > VLV
>>
>>It still needs filtering.
>>
>>Digital approximations to derivatives come in many forms. The simplest 
>>and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications, 
>>y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of 
>>latency. Rick Lyons improves on that with two more delay terms and the 
>>corresponding extra latency. I'm not certain that I'm at liberty to 
>>provide more details. I expect that he will.
>>
>>Jerry
>
>Hi Jerry,
>  If you're referring to the differentiator that 
>I think you are, then it's described in detail 
>at:
>
>http://www.dsprelated.com/showarticle/35.php
>
>See Ya',
>[-Rick-]
>No. 6: "What do you want?"
>No. 2: "Information."
>No. 6: "Who are you?"
>No. 2: "I am the new No. 2."
>No. 6: "Who is No. 1?"
>No. 2: "You are No. 6."
>No. 6: "I am not a number. I am a free man!"
>

Hello everybody,

I have to say: "Thank you for your advices, some (= everyone :-)) of them
were very useful for me!" 

At the moment I am testing differentiator described by Rick Lyons in his
article (http://www.dsprelated.com/showarticle/35.php). It seems, it will
be work as we with my boss want. The output from differentiator is attached
to moving average filter (16th order).  Resulting value of derivative is
stable now. Super :-). I think, this solution is the best of we could
choose.

Thanks a lot.

Miroslav Martisek, Bohemia

Did it come to your mind that a combination of differentiator and 
averager makes a bandpass filter?

On Mon, 10 Jun 2013 07:31:15 -0500, "Mimar" <94571@dsprelated> wrote:

>>On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:
>>
>>>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>>>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>>>>>
>>>>>> could somebody give me an advice? At the moment I am solving
>>>>>> interesting problem. I have been using SW PLL with SOGI circuit to
>>>>>> obtain grid frequency
>>>>
>>>>
>>>>>
>>>>> You could design a simple control loop with an integrator in the
>>>>> feedback path. This will give you band-limited differentiation ie a
>>>>> slope of 6dB/octave.
>>>>
>>>> Good point. As the OP is using PLL, the output of phase detector is
>>>> derivative of frequency.
>>>>
>>>> VLV
>>>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>>> > On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>> >> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>> >>>
>>> >>> could somebody give me an advice? At the moment I am solving
>>> >>> interesting problem. I have been using SW PLL with SOGI circuit to
>>> >>> obtain grid frequency
>>> >
>>> >
>>> >>
>>> >> You could design a simple control loop with an integrator in the
>>> >> feedback path. This will give you band-limited differentiation ie a
>>> >> slope of 6dB/octave.
>>> >
>>> > Good point. As the OP is using PLL, the output of phase detector is
>>> > derivative of frequency.
>>> >
>>> > VLV
>>>
>>>It still needs filtering.
>>>
>>>Digital approximations to derivatives come in many forms. The simplest 
>>>and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications, 
>>>y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of 
>>>latency. Rick Lyons improves on that with two more delay terms and the 
>>>corresponding extra latency. I'm not certain that I'm at liberty to 
>>>provide more details. I expect that he will.
>>>
>>>Jerry
>>
>>Hi Jerry,
>>  If you're referring to the differentiator that 
>>I think you are, then it's described in detail 
>>at:
>>
>>http://www.dsprelated.com/showarticle/35.php
>>
>>See Ya',
>>[-Rick-]
>>No. 6: "What do you want?"
>>No. 2: "Information."
>>No. 6: "Who are you?"
>>No. 2: "I am the new No. 2."
>>No. 6: "Who is No. 1?"
>>No. 2: "You are No. 6."
>>No. 6: "I am not a number. I am a free man!"
>>
>
>Hello everybody,
>
>I have to say: "Thank you for your advices, some (= everyone :-)) of them
>were very useful for me!" 
>
>At the moment I am testing differentiator described by Rick Lyons in his
>article (http://www.dsprelated.com/showarticle/35.php). It seems, it will
>be work as we with my boss want. The output from differentiator is attached
>to moving average filter (16th order).  Resulting value of derivative is
>stable now. Super :-). I think, this solution is the best of we could
>choose.
>
>Thanks a lot.
>
>Miroslav Martisek, Bohemia

Hello Miroslav Martisek,
    Please forgive me for my ignorance.
What do you mean by Bohemia?

In the United States we have Bohemian 
beer. But I confess, I don't know what 
Bohemia or Bohemian means.

[-Rick-]



>

On Tuesday, June 11, 2013 5:25:35 PM UTC+12, Rick Lyons wrote:
> On Mon, 10 Jun 2013 07:31:15 -0500, "Mimar" <94571@dsprelated> wrote:
> 
> 
> 
> >>On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:
> 
> >>
> 
> >>>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
> 
> >>>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
> 
> >>>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
> 
> >>>>>>
> 
> >>>>>> could somebody give me an advice? At the moment I am solving
> 
> >>>>>> interesting problem. I have been using SW PLL with SOGI circuit to
> 
> >>>>>> obtain grid frequency
> 
> >>>>
> 
> >>>>
> 
> >>>>>
> 
> >>>>> You could design a simple control loop with an integrator in the
> 
> >>>>> feedback path. This will give you band-limited differentiation ie a
> 
> >>>>> slope of 6dB/octave.
> 
> >>>>
> 
> >>>> Good point. As the OP is using PLL, the output of phase detector is
> 
> >>>> derivative of frequency.
> 
> >>>>
> 
> >>>> VLV
> 
> >>>On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
> 
> >>> > On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
> 
> >>> >> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
> 
> >>> >>>
> 
> >>> >>> could somebody give me an advice? At the moment I am solving
> 
> >>> >>> interesting problem. I have been using SW PLL with SOGI circuit to
> 
> >>> >>> obtain grid frequency
> 
> >>> >
> 
> >>> >
> 
> >>> >>
> 
> >>> >> You could design a simple control loop with an integrator in the
> 
> >>> >> feedback path. This will give you band-limited differentiation ie a
> 
> >>> >> slope of 6dB/octave.
> 
> >>> >
> 
> >>> > Good point. As the OP is using PLL, the output of phase detector is
> 
> >>> > derivative of frequency.
> 
> >>> >
> 
> >>> > VLV
> 
> >>>
> 
> >>>It still needs filtering.
> 
> >>>
> 
> >>>Digital approximations to derivatives come in many forms. The simplest 
> 
> >>>and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications, 
> 
> >>>y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of 
> 
> >>>latency. Rick Lyons improves on that with two more delay terms and the 
> 
> >>>corresponding extra latency. I'm not certain that I'm at liberty to 
> 
> >>>provide more details. I expect that he will.
> 
> >>>
> 
> >>>Jerry
> 
> >>
> 
> >>Hi Jerry,
> 
> >>  If you're referring to the differentiator that 
> 
> >>I think you are, then it's described in detail 
> 
> >>at:
> 
> >>
> 
> >>http://www.dsprelated.com/showarticle/35.php
> 
> >>
> 
> >>See Ya',
> 
> >>[-Rick-]
> 
> >>No. 6: "What do you want?"
> 
> >>No. 2: "Information."
> 
> >>No. 6: "Who are you?"
> 
> >>No. 2: "I am the new No. 2."
> 
> >>No. 6: "Who is No. 1?"
> 
> >>No. 2: "You are No. 6."
> 
> >>No. 6: "I am not a number. I am a free man!"
> 
> >>
> 
> >
> 
> >Hello everybody,
> 
> >
> 
> >I have to say: "Thank you for your advices, some (= everyone :-)) of them
> 
> >were very useful for me!" 
> 
> >
> 
> >At the moment I am testing differentiator described by Rick Lyons in his
> 
> >article (http://www.dsprelated.com/showarticle/35.php). It seems, it will
> 
> >be work as we with my boss want. The output from differentiator is attached
> 
> >to moving average filter (16th order).  Resulting value of derivative is
> 
> >stable now. Super :-). I think, this solution is the best of we could
> 
> >choose.
> 
> >
> 
> >Thanks a lot.
> 
> >
> 
> >Miroslav Martisek, Bohemia
> 
> 
> 
> Hello Miroslav Martisek,
> 
>     Please forgive me for my ignorance.
> 
> What do you mean by Bohemia?
> 
> 
> 
> In the United States we have Bohemian 
> 
> beer. But I confess, I don't know what 
> 
> Bohemia or Bohemian means.
> 
> 
> 
> [-Rick-]
> 
> 
> 
> 
> 
> 
> 
> >

A lifestyle, arty type Bohemian existence - from Europe.

Bohemianism is the practice of an unconventional lifestyle, often in the company of like-minded people, with few permanent ties, involving musical, artistic, or literary pursuits. In this context, Bohemians may be wanderers, adventurers, or vagabonds.
This use of the word bohemian first appeared in the English language in the nineteenth century[1] to describe the non-traditional lifestyles of marginalized and impoverished artists, writers, journalists, musicians, and actors in major European cities.

On Tuesday, June 11, 2013 11:07:22 AM UTC+12, Vladimir Vassilevsky wrote:
> Did it come to your mind that a combination of differentiator and 
> 
> averager makes a bandpass filter?

not a very good one though, poor slope.

Rick Lyons <R.Lyons@_bogus_ieee.org> wrote:
>    Please forgive me for my ignorance.
> What do you mean by Bohemia?

http://en.wikipedia.org/wiki/Bohemia
> 
> In the United States we have Bohemian 
> beer. But I confess, I don't know what 
> Bohemia or Bohemian means.

http://en.wikipedia.org/wiki/Beer_in_the_Czech_Republic

;)

On 11.6.13 8:25 , Rick Lyons wrote:
> On Mon, 10 Jun 2013 07:31:15 -0500, "Mimar" <94571@dsprelated> wrote:
>
>>> On Sat, 08 Jun 2013 23:24:01 -0400, Jerry Avins <jya@ieee.org> wrote:
>>>
>>>> On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>>>>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>>>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>>>>>>
>>>>>>> could somebody give me an advice? At the moment I am solving
>>>>>>> interesting problem. I have been using SW PLL with SOGI circuit to
>>>>>>> obtain grid frequency
>>>>>
>>>>>
>>>>>>
>>>>>> You could design a simple control loop with an integrator in the
>>>>>> feedback path. This will give you band-limited differentiation ie a
>>>>>> slope of 6dB/octave.
>>>>>
>>>>> Good point. As the OP is using PLL, the output of phase detector is
>>>>> derivative of frequency.
>>>>>
>>>>> VLV
>>>> On 6/7/2013 12:56 PM, Vladimir Vassilevsky wrote:
>>>>> On 6/6/2013 4:11 PM, gyansorova@gmail.com wrote:
>>>>>> On Thursday, June 6, 2013 7:11:53 PM UTC+12, Mimar wrote:
>>>>>>>
>>>>>>> could somebody give me an advice? At the moment I am solving
>>>>>>> interesting problem. I have been using SW PLL with SOGI circuit to
>>>>>>> obtain grid frequency
>>>>>
>>>>>
>>>>>>
>>>>>> You could design a simple control loop with an integrator in the
>>>>>> feedback path. This will give you band-limited differentiation ie a
>>>>>> slope of 6dB/octave.
>>>>>
>>>>> Good point. As the OP is using PLL, the output of phase detector is
>>>>> derivative of frequency.
>>>>>
>>>>> VLV
>>>>
>>>> It still needs filtering.
>>>>
>>>> Digital approximations to derivatives come in many forms. The simplest
>>>> and most intuitive is simply y[n]=x[n-1]-x[n]. For many applications,
>>>> y[n]=.5(x[n-2]-2.c[n-1]+x[n]) is better. The cost is an extra clock of
>>>> latency. Rick Lyons improves on that with two more delay terms and the
>>>> corresponding extra latency. I'm not certain that I'm at liberty to
>>>> provide more details. I expect that he will.
>>>>
>>>> Jerry
>>>
>>> Hi Jerry,
>>>   If you're referring to the differentiator that
>>> I think you are, then it's described in detail
>>> at:
>>>
>>> http://www.dsprelated.com/showarticle/35.php
>>>
>>> See Ya',
>>> [-Rick-]
>>> No. 6: "What do you want?"
>>> No. 2: "Information."
>>> No. 6: "Who are you?"
>>> No. 2: "I am the new No. 2."
>>> No. 6: "Who is No. 1?"
>>> No. 2: "You are No. 6."
>>> No. 6: "I am not a number. I am a free man!"
>>>
>>
>> Hello everybody,
>>
>> I have to say: "Thank you for your advices, some (= everyone :-)) of them
>> were very useful for me!"
>>
>> At the moment I am testing differentiator described by Rick Lyons in his
>> article (http://www.dsprelated.com/showarticle/35.php). It seems, it will
>> be work as we with my boss want. The output from differentiator is attached
>> to moving average filter (16th order).  Resulting value of derivative is
>> stable now. Super :-). I think, this solution is the best of we could
>> choose.
>>
>> Thanks a lot.
>>
>> Miroslav Martisek, Bohemia
>
> Hello Miroslav Martisek,
>      Please forgive me for my ignorance.
> What do you mean by Bohemia?
>
> In the United States we have Bohemian
> beer. But I confess, I don't know what
> Bohemia or Bohemian means.
>
> [-Rick-]

Hello Rick,

Bohemia (German: B&#4294967295;hmenland) is the western part of current Czech 
Republic, the home of world's best beer.

See: <https://en.wikipedia.org/wiki/Bohemia>

-- 

-Tauno