Reverse summation of a complex exponential

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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 $a_k^(-),l$ ?







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














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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 $a_k^(-),l$ ?









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asked Jul 16 at 13:53









Khaled Ismail

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  • 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
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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.






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    1 Answer
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    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

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