Pole-zeros of a real-valued causal FIR system












5












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Could someone please help me with the following question?



Below is the magnitude response of a real-valued causal linear phase FIR system of order N = 6. Determine the location of poles and zeros.



enter image description here



I know that for FIR systems all the poles are located at the origin, so we have a pole of order six at the origin. Also from the given diagram, I can say that we have a zero at 0.3pi and one at 0.8pi (both on the unit circle). Now since the system is real-valued, location of poles and zeros should be symmetric w.r.t. the real axis. But I don't know about the two other zeros?



Also, what about the pick in the diagram? Does it mean we have another pole?










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    5












    $begingroup$


    Could someone please help me with the following question?



    Below is the magnitude response of a real-valued causal linear phase FIR system of order N = 6. Determine the location of poles and zeros.



    enter image description here



    I know that for FIR systems all the poles are located at the origin, so we have a pole of order six at the origin. Also from the given diagram, I can say that we have a zero at 0.3pi and one at 0.8pi (both on the unit circle). Now since the system is real-valued, location of poles and zeros should be symmetric w.r.t. the real axis. But I don't know about the two other zeros?



    Also, what about the pick in the diagram? Does it mean we have another pole?










    share|improve this question









    $endgroup$















      5












      5








      5


      1



      $begingroup$


      Could someone please help me with the following question?



      Below is the magnitude response of a real-valued causal linear phase FIR system of order N = 6. Determine the location of poles and zeros.



      enter image description here



      I know that for FIR systems all the poles are located at the origin, so we have a pole of order six at the origin. Also from the given diagram, I can say that we have a zero at 0.3pi and one at 0.8pi (both on the unit circle). Now since the system is real-valued, location of poles and zeros should be symmetric w.r.t. the real axis. But I don't know about the two other zeros?



      Also, what about the pick in the diagram? Does it mean we have another pole?










      share|improve this question









      $endgroup$




      Could someone please help me with the following question?



      Below is the magnitude response of a real-valued causal linear phase FIR system of order N = 6. Determine the location of poles and zeros.



      enter image description here



      I know that for FIR systems all the poles are located at the origin, so we have a pole of order six at the origin. Also from the given diagram, I can say that we have a zero at 0.3pi and one at 0.8pi (both on the unit circle). Now since the system is real-valued, location of poles and zeros should be symmetric w.r.t. the real axis. But I don't know about the two other zeros?



      Also, what about the pick in the diagram? Does it mean we have another pole?







      fir poles-zeros






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      asked Mar 27 at 19:40









      NioushaNiousha

      1646




      1646






















          2 Answers
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          Note the difference between the zeros at $0.3 pi$ and at $0.8 pi$.



          The first one is clearly a zero crossing, much like $abs(x)$ at $x=0$.



          At $theta = 0.8 pi$, however, the curve is tangent to the horizontal axis, much like $x^2$ at $x=0$. So you have a doulbe zero here.



          So your zeros are:




          • 2 zeros at $z = e^{pm j 0.3 pi}$

          • 2 double zeros at $z = e^{pm j 0.8 pi}$






          share|improve this answer









          $endgroup$





















            1












            $begingroup$

            Causality places the transfer-function poles at $z=0$, for a FIR filter.



            A FIR filter need not necessarily be causal, in which case some or all of its poles reside at $z=infty$ (if not at $z=0$). In any of these cases, the poles play no role in shaping frequency response, since they remain equidistant from the unit circle.



            (A value of $k$ in the range of $[-1, 1]$ can place conjugate pole pairs anywhere on the unit circle, where they are most effectual in shaping frequency response.)
            $$begin{aligned}
            frac{z^2 +2kz + 1}{z^2} &mbox{implies} y_n=x_n + 2kx_{n-1} + x_{n-2} \
            z^2 +2kz + 1 &mbox{implies} y_n=x_{n+2} + 2kx_{n+1} + x_{n}
            end{aligned}$$






            share|improve this answer








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              2 Answers
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              active

              oldest

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              2 Answers
              2






              active

              oldest

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              active

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              active

              oldest

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              10












              $begingroup$

              Note the difference between the zeros at $0.3 pi$ and at $0.8 pi$.



              The first one is clearly a zero crossing, much like $abs(x)$ at $x=0$.



              At $theta = 0.8 pi$, however, the curve is tangent to the horizontal axis, much like $x^2$ at $x=0$. So you have a doulbe zero here.



              So your zeros are:




              • 2 zeros at $z = e^{pm j 0.3 pi}$

              • 2 double zeros at $z = e^{pm j 0.8 pi}$






              share|improve this answer









              $endgroup$


















                10












                $begingroup$

                Note the difference between the zeros at $0.3 pi$ and at $0.8 pi$.



                The first one is clearly a zero crossing, much like $abs(x)$ at $x=0$.



                At $theta = 0.8 pi$, however, the curve is tangent to the horizontal axis, much like $x^2$ at $x=0$. So you have a doulbe zero here.



                So your zeros are:




                • 2 zeros at $z = e^{pm j 0.3 pi}$

                • 2 double zeros at $z = e^{pm j 0.8 pi}$






                share|improve this answer









                $endgroup$
















                  10












                  10








                  10





                  $begingroup$

                  Note the difference between the zeros at $0.3 pi$ and at $0.8 pi$.



                  The first one is clearly a zero crossing, much like $abs(x)$ at $x=0$.



                  At $theta = 0.8 pi$, however, the curve is tangent to the horizontal axis, much like $x^2$ at $x=0$. So you have a doulbe zero here.



                  So your zeros are:




                  • 2 zeros at $z = e^{pm j 0.3 pi}$

                  • 2 double zeros at $z = e^{pm j 0.8 pi}$






                  share|improve this answer









                  $endgroup$



                  Note the difference between the zeros at $0.3 pi$ and at $0.8 pi$.



                  The first one is clearly a zero crossing, much like $abs(x)$ at $x=0$.



                  At $theta = 0.8 pi$, however, the curve is tangent to the horizontal axis, much like $x^2$ at $x=0$. So you have a doulbe zero here.



                  So your zeros are:




                  • 2 zeros at $z = e^{pm j 0.3 pi}$

                  • 2 double zeros at $z = e^{pm j 0.8 pi}$







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Mar 27 at 20:10









                  JuanchoJuancho

                  3,8901416




                  3,8901416























                      1












                      $begingroup$

                      Causality places the transfer-function poles at $z=0$, for a FIR filter.



                      A FIR filter need not necessarily be causal, in which case some or all of its poles reside at $z=infty$ (if not at $z=0$). In any of these cases, the poles play no role in shaping frequency response, since they remain equidistant from the unit circle.



                      (A value of $k$ in the range of $[-1, 1]$ can place conjugate pole pairs anywhere on the unit circle, where they are most effectual in shaping frequency response.)
                      $$begin{aligned}
                      frac{z^2 +2kz + 1}{z^2} &mbox{implies} y_n=x_n + 2kx_{n-1} + x_{n-2} \
                      z^2 +2kz + 1 &mbox{implies} y_n=x_{n+2} + 2kx_{n+1} + x_{n}
                      end{aligned}$$






                      share|improve this answer








                      New contributor




                      Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.






                      $endgroup$


















                        1












                        $begingroup$

                        Causality places the transfer-function poles at $z=0$, for a FIR filter.



                        A FIR filter need not necessarily be causal, in which case some or all of its poles reside at $z=infty$ (if not at $z=0$). In any of these cases, the poles play no role in shaping frequency response, since they remain equidistant from the unit circle.



                        (A value of $k$ in the range of $[-1, 1]$ can place conjugate pole pairs anywhere on the unit circle, where they are most effectual in shaping frequency response.)
                        $$begin{aligned}
                        frac{z^2 +2kz + 1}{z^2} &mbox{implies} y_n=x_n + 2kx_{n-1} + x_{n-2} \
                        z^2 +2kz + 1 &mbox{implies} y_n=x_{n+2} + 2kx_{n+1} + x_{n}
                        end{aligned}$$






                        share|improve this answer








                        New contributor




                        Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                        Check out our Code of Conduct.






                        $endgroup$
















                          1












                          1








                          1





                          $begingroup$

                          Causality places the transfer-function poles at $z=0$, for a FIR filter.



                          A FIR filter need not necessarily be causal, in which case some or all of its poles reside at $z=infty$ (if not at $z=0$). In any of these cases, the poles play no role in shaping frequency response, since they remain equidistant from the unit circle.



                          (A value of $k$ in the range of $[-1, 1]$ can place conjugate pole pairs anywhere on the unit circle, where they are most effectual in shaping frequency response.)
                          $$begin{aligned}
                          frac{z^2 +2kz + 1}{z^2} &mbox{implies} y_n=x_n + 2kx_{n-1} + x_{n-2} \
                          z^2 +2kz + 1 &mbox{implies} y_n=x_{n+2} + 2kx_{n+1} + x_{n}
                          end{aligned}$$






                          share|improve this answer








                          New contributor




                          Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                          Check out our Code of Conduct.






                          $endgroup$



                          Causality places the transfer-function poles at $z=0$, for a FIR filter.



                          A FIR filter need not necessarily be causal, in which case some or all of its poles reside at $z=infty$ (if not at $z=0$). In any of these cases, the poles play no role in shaping frequency response, since they remain equidistant from the unit circle.



                          (A value of $k$ in the range of $[-1, 1]$ can place conjugate pole pairs anywhere on the unit circle, where they are most effectual in shaping frequency response.)
                          $$begin{aligned}
                          frac{z^2 +2kz + 1}{z^2} &mbox{implies} y_n=x_n + 2kx_{n-1} + x_{n-2} \
                          z^2 +2kz + 1 &mbox{implies} y_n=x_{n+2} + 2kx_{n+1} + x_{n}
                          end{aligned}$$







                          share|improve this answer








                          New contributor




                          Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                          Check out our Code of Conduct.









                          share|improve this answer



                          share|improve this answer






                          New contributor




                          Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                          Check out our Code of Conduct.









                          answered Mar 28 at 7:32









                          KevinKevin

                          111




                          111




                          New contributor




                          Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                          Check out our Code of Conduct.





                          New contributor





                          Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                          Check out our Code of Conduct.






                          Kevin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                          Check out our Code of Conduct.






























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