11/13/2005 6.111: A Music Transcriber 1Music TranscriberMusic Transcriber11/13/2005 6.111: A Music Transcriber 2Note RecognizerVideo DisplayMetronomebeat to_LEDnote 5duration 2newnoteaudio inputto_monitor 5Overall Block Diagram11/13/2005 6.111: A Music Transcriber 3¾ Use Codec to amplify the analog audio signal and convert it to a digital signal.¾ Obtain a frequency spectrum of the audio sample using FFT.¾ Detect the peak frequency of the spectrum.¾ Convert this into a recognizable frequency in Hertz.¾ Use a look-up table to relate the peak frequency to a musical note.¾ Use a counter to measure the duration of a note as the number of beats between a note change. The frequency of beats depends on a user defined tempo.Note Recognition Module4A/D CONVERTERANALOG AMPLIFIERFFTPEAK DETECTORTEMPOCLOCKCOUNTERCOMPARELOOK-UP TABLECODECReset (global)Clock (global)INPUTTEMPOBeatDURATION2NEW_NOTEBEATNew_NotePeak_IndexNOTE5AudioReadyReal_Data8NOTEAUDIO INTERFACEPRE-FFTPulse_ReadyAudio_ContIm_Data88810Index105Note Recognizer11/13/2005 6.111: A Music Transcriber 5Video DisplayProduces music stave video output from note values and durationsTracker¾ Follows the writing on the stave, translates the note value into its correct position on the screen. ¾ Tells the Video where to display the next note.Video¾ Uses sprites to display background staves and clefs.¾ Uses a moveable sprite to display a new note at a given position¾ The “note” sprite reads different note fonts from a ROM, so as to display the different shapes.¾ The shape of the note is given by its duration.11/13/2005 6.111: A Music Transcriber 6Video ModuleXVGA1024x768@60HzTrackernote 5newnoteresetduration 2startcx 10cy 10reset10 hcount9 vcounthsyncvsyncpixel 3to_monitor 5Video DisplayCoordinates for note position11/13/2005 6.111: A Music Transcriber 7Video RAM(1024*764) x 1Note displaydurationcxto_XVGAVideo ModulecyStave/Treble clefDisplayvideoWRWEColor 13videoCount/addrconverterhcountvcountADDRREADpixel apixel bpixelROM 4 x 961ORORNon-erasable video outputROM storing note fonts(full note, quarter note…)Convert black & white to colorSet of video signals from XVGA(hcount, hsync, vcount…)11/13/2005 6.111: A Music Transcriber 8Additional Features¾Rythmical complexity• Bars• Odd rythms• Tied notes¾ Musical Vocabulary• Higher timing precision• Larger note span¾ Complex
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