This　paper　presents　a　4　kbit/s　CELP　speech　coder　that　utilizes　the　nonuniform　and　part-searching-area　algebraic　codebook　technologies　to　overcome　the　insufficient　number　of　signed　pulses　in　fixed　codebook　(FCB).　The　nonuniform　algebraic　codebook　is　based　on　the　nonuniform　statistical　properties　of　the　FCB.　The　part-searching-area　utilizes　the　periodicity　of　the　FCB　excitation　signal　at　low　bit　rate.　The　latter　is　only　employed　when　pitch　delay　is　small　enough.　We　also　find　that　preserving　the　continuity　of　pitch　is　very　important　for　voiced　segment　if　these　two　technologies　are　used.　So　different　pitch-detect　methods　are　employed　for　voiced/unvoiced　frame.　Subjective　and　objective　test　results　indicate　that　the　qualities　of　reconstructed　speech　are　improved,　especially　for　the　female　speakers.　©　2004　IEEE.