Reverse summation of a complex exponential

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
1
down vote

favorite












In the equation below:
$$s_l(t)=sum_k=-lfloorN_sc^RB/2rfloor^lceilN_sc^RB/2rceil-1a_k^(-),l^,.e^j2pi(k+1/2)Delta f(t-N_CP,lT_s)$$



where: $0le tlt (N_CP,l+N)times T_s$ , $k^(-)=k+lfloorN_sc^RB/2rfloor$, $N = 2048$, $Delta f=15kHz$



I know the values of: $N_sc^RB$, $N_CP,l$ and $T_s$.



Simply put, I want to solve for $a_k^(-),l$ which is a vector of values. And I know all the values of the other parameters. $s_l(t)$ is a vector as well which values I know.



Is it possible to reverse the order of the equation to calculate for $a_k^(-),l$ ?







share|cite|improve this question



















  • you are using way too many letters
    – mercio
    Jul 16 at 15:04














up vote
1
down vote

favorite












In the equation below:
$$s_l(t)=sum_k=-lfloorN_sc^RB/2rfloor^lceilN_sc^RB/2rceil-1a_k^(-),l^,.e^j2pi(k+1/2)Delta f(t-N_CP,lT_s)$$



where: $0le tlt (N_CP,l+N)times T_s$ , $k^(-)=k+lfloorN_sc^RB/2rfloor$, $N = 2048$, $Delta f=15kHz$



I know the values of: $N_sc^RB$, $N_CP,l$ and $T_s$.



Simply put, I want to solve for $a_k^(-),l$ which is a vector of values. And I know all the values of the other parameters. $s_l(t)$ is a vector as well which values I know.



Is it possible to reverse the order of the equation to calculate for $a_k^(-),l$ ?







share|cite|improve this question



















  • you are using way too many letters
    – mercio
    Jul 16 at 15:04












up vote
1
down vote

favorite









up vote
1
down vote

favorite











In the equation below:
$$s_l(t)=sum_k=-lfloorN_sc^RB/2rfloor^lceilN_sc^RB/2rceil-1a_k^(-),l^,.e^j2pi(k+1/2)Delta f(t-N_CP,lT_s)$$



where: $0le tlt (N_CP,l+N)times T_s$ , $k^(-)=k+lfloorN_sc^RB/2rfloor$, $N = 2048$, $Delta f=15kHz$



I know the values of: $N_sc^RB$, $N_CP,l$ and $T_s$.



Simply put, I want to solve for $a_k^(-),l$ which is a vector of values. And I know all the values of the other parameters. $s_l(t)$ is a vector as well which values I know.



Is it possible to reverse the order of the equation to calculate for $a_k^(-),l$ ?







share|cite|improve this question











In the equation below:
$$s_l(t)=sum_k=-lfloorN_sc^RB/2rfloor^lceilN_sc^RB/2rceil-1a_k^(-),l^,.e^j2pi(k+1/2)Delta f(t-N_CP,lT_s)$$



where: $0le tlt (N_CP,l+N)times T_s$ , $k^(-)=k+lfloorN_sc^RB/2rfloor$, $N = 2048$, $Delta f=15kHz$



I know the values of: $N_sc^RB$, $N_CP,l$ and $T_s$.



Simply put, I want to solve for $a_k^(-),l$ which is a vector of values. And I know all the values of the other parameters. $s_l(t)$ is a vector as well which values I know.



Is it possible to reverse the order of the equation to calculate for $a_k^(-),l$ ?









share|cite|improve this question










share|cite|improve this question




share|cite|improve this question









asked Jul 16 at 13:53









Khaled Ismail

61




61











  • you are using way too many letters
    – mercio
    Jul 16 at 15:04
















  • you are using way too many letters
    – mercio
    Jul 16 at 15:04















you are using way too many letters
– mercio
Jul 16 at 15:04




you are using way too many letters
– mercio
Jul 16 at 15:04










1 Answer
1






active

oldest

votes

















up vote
0
down vote













This is a long comment, that's why I put it as an answer. By the looks of it, this is some sort of Discrete Fourier Transform. To reverse it, you would just use the Inverse Discrete Fourier Transform.



$$X_k = sum_n=0^N-1 x_ncdot e^-frac 2pi iNkn ,$$



$$x_n = frac1N sum_k=0^N-1 X_kcdot e^i 2 pi k n / N .$$



Also, based on the facts that you used $j$ for the unit of imaginary numbers, and having units of $Hz$; I believe the context of this equation is Electrical Engineering. And Fourier Transforms are widely used in EE.






share|cite|improve this answer





















    Your Answer




    StackExchange.ifUsing("editor", function ()
    return StackExchange.using("mathjaxEditing", function ()
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    );
    );
    , "mathjax-editing");

    StackExchange.ready(function()
    var channelOptions =
    tags: "".split(" "),
    id: "69"
    ;
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function()
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled)
    StackExchange.using("snippets", function()
    createEditor();
    );

    else
    createEditor();

    );

    function createEditor()
    StackExchange.prepareEditor(
    heartbeatType: 'answer',
    convertImagesToLinks: true,
    noModals: false,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    );



    );








     

    draft saved


    draft discarded


















    StackExchange.ready(
    function ()
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2853429%2freverse-summation-of-a-complex-exponential%23new-answer', 'question_page');

    );

    Post as a guest






























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    0
    down vote













    This is a long comment, that's why I put it as an answer. By the looks of it, this is some sort of Discrete Fourier Transform. To reverse it, you would just use the Inverse Discrete Fourier Transform.



    $$X_k = sum_n=0^N-1 x_ncdot e^-frac 2pi iNkn ,$$



    $$x_n = frac1N sum_k=0^N-1 X_kcdot e^i 2 pi k n / N .$$



    Also, based on the facts that you used $j$ for the unit of imaginary numbers, and having units of $Hz$; I believe the context of this equation is Electrical Engineering. And Fourier Transforms are widely used in EE.






    share|cite|improve this answer

























      up vote
      0
      down vote













      This is a long comment, that's why I put it as an answer. By the looks of it, this is some sort of Discrete Fourier Transform. To reverse it, you would just use the Inverse Discrete Fourier Transform.



      $$X_k = sum_n=0^N-1 x_ncdot e^-frac 2pi iNkn ,$$



      $$x_n = frac1N sum_k=0^N-1 X_kcdot e^i 2 pi k n / N .$$



      Also, based on the facts that you used $j$ for the unit of imaginary numbers, and having units of $Hz$; I believe the context of this equation is Electrical Engineering. And Fourier Transforms are widely used in EE.






      share|cite|improve this answer























        up vote
        0
        down vote










        up vote
        0
        down vote









        This is a long comment, that's why I put it as an answer. By the looks of it, this is some sort of Discrete Fourier Transform. To reverse it, you would just use the Inverse Discrete Fourier Transform.



        $$X_k = sum_n=0^N-1 x_ncdot e^-frac 2pi iNkn ,$$



        $$x_n = frac1N sum_k=0^N-1 X_kcdot e^i 2 pi k n / N .$$



        Also, based on the facts that you used $j$ for the unit of imaginary numbers, and having units of $Hz$; I believe the context of this equation is Electrical Engineering. And Fourier Transforms are widely used in EE.






        share|cite|improve this answer













        This is a long comment, that's why I put it as an answer. By the looks of it, this is some sort of Discrete Fourier Transform. To reverse it, you would just use the Inverse Discrete Fourier Transform.



        $$X_k = sum_n=0^N-1 x_ncdot e^-frac 2pi iNkn ,$$



        $$x_n = frac1N sum_k=0^N-1 X_kcdot e^i 2 pi k n / N .$$



        Also, based on the facts that you used $j$ for the unit of imaginary numbers, and having units of $Hz$; I believe the context of this equation is Electrical Engineering. And Fourier Transforms are widely used in EE.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Jul 16 at 17:00









        Ali

        1,144924




        1,144924






















             

            draft saved


            draft discarded


























             


            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2853429%2freverse-summation-of-a-complex-exponential%23new-answer', 'question_page');

            );

            Post as a guest













































































            Comments

            Popular posts from this blog

            What is the equation of a 3D cone with generalised tilt?

            Relationship between determinant of matrix and determinant of adjoint?

            Color the edges and diagonals of a regular polygon