7.Ïðîåêòèðîâàíèå öèôðîâîãî ôèëüòðà ÏÇ


     Ïðîåêòèðîâàíèå ïîëîñîâîãî çàãðàæäàþùåãî ôèëüòðà ïðîèçâîäèòñÿ ñ èñïîëüçîâàíèåì òîé æå ïðîãðàììû MatLab. Ìîæíî èñïîëüçîâàòü ðåçóëüòàòû ðàñ÷åòà ôèëüòðîâ Í× è Â×, åñëè ôèëüòð ïðîåêòèðóåòñÿ â âèäå ïàðàëëåëüíîãî ñîåäèíåíèÿ  äâóõ  ôèëüòðîâ  Í× è Â×. Ïðè ýòîì À×Õ ýòèõ ôèëüòðîâ âûáèðàåòñÿ òàêîé,  ÷òîáû ðåçóëüòèðóþùàÿ À×Õ ïîëîñîâîãî çàãðàæäàþùåãî ôèëüòðà îòâå÷àëà çàäàííûì òðåáîâàíèÿì.

                                 - - - - - - -

           Âõîä                --------              Âûõîä

                    -------+-+  ÔÍ×  +--+-----

                        ¦           --------           |

                        ¦            ÏÇÔ             |

                        ¦           --------            |

                        ---+-+  ÔÂ×  +-+---

                                   --------

                                - - - - - - -

               Ðèñ.5.Ñòðóêòóðíàÿ ñõåìà ôèëüòðà ÏÇ

 

   H(w)

     +----¬

     ¦        ¬                      Ôèëüòð  íèæíèõ ÷àñòîò

     ¦          ¬

     L----+--+-----------------

           F1 F2

 

    H(w)

     ¦                  -----

     ¦                -           Ôèëüòð  âåðõíèõ ÷àñòîò

     ¦               -

     L---------+--+--------

                  F3 F4

 

    H(w)

     ¦ ----¬                ----

     ¦         ¬            -           Ïîëîñîâîé çàãðàæäàþùèé ôèëüòð

     ¦           ¬        -

     L----+--+-----+--+--------

            F1 F2    F3 F4


                   Ðèñ.6. Àìïëèòóäíî-÷àñòîòíûå

                       õàðàêòåðèñòèêè ÏÇÔ