4. 1. (sound source) : (sound wave) :.,,,,. 180 1
( ) 1 : Hz, KHz, MHz 1 Hz = 1 1 KHz = 1,000 Hz, 1 MHz = 1,000 KHz 20 Hz ~ 20 KHz (, ) + 0-1 1 2 3 4 2 3 4 + 0-1 2 3 4 5 1 6 7 8 2 3 4 2
( ), (db) : (, intensity)) +1 +1 +1 0 0 0-1 +1 + -1 +1 + -1 +1 + 0 0 0-1 -1-1 = = = +2 +2 +2 +1 0 0 0-1 3-2 -2-2
(decibel : db) (, intensity)) db = 20 log 10 (A/B) A : B : B=2.83*10-4 dyne/cm 2 1dyne 1g 1cm/sec 2 100 db 120 db (threshold of pain) 4
ADC DAC ADC : Analog-to-Digital Converter DAC : Digital-to-Analog Converter : 5
Sampling rate / Hz, KHz (Sampling Rate) sampling rate (WHY?) 2 sampling. f 0 [Hz] 2 f 0 [Hz] sampling Sampling Rate Sampling Rate Sampling Rate(KHz) 8 11.025 18.9 22.05 32 37.8 44.1 48 NeXT Workstation, MPC-I CD-ROM/XA( ) Macintosh, MPC-I Digital radio, HDTV CD-ROM/XA( ) CD, MPC-II DAT 6
Resolution( ) (Resolution) Sampling ( ), Resolution: bit 8 bit : 256 16 bit : 65,656 Sampling Rate Resolution 7
PCM(Pulse Code Modulation) sampling ADC. DAC. :. : sampling frequency resolution DPCM(Differential PCM) 4 (0) (1) 3 ADPCM(Adaptive Differential PCM) CD-I(CD Interactive) PCM DPCM 0 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 0 1 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 1 0 12 14 18 12 10 MSB LSB 0 0 1 0 0 1 0 0 +2 +4 MSB LSB 1 1 1 0 1 0 1 0-6 -2 8
FM(Frequency Modulation) 9
Waveform(wave) (.wav ) MS Windows PCM Sound Card ADC, DAC Sampling Frequency 44.1 KHz, 22 KHz, 11 KHz Wave CD-Audio /,, mixing 44.1 KHz frequency sampling sampling 16 10
:. :,. 1922 J.Q. Stewart resonance circuit 1939 H. Dudley VODEC 10 DSP(Digital Signal Processing) 11
(PCM, ADPCM, ADM ) Analysis-Synthesis(Formant, LPC) Formant : ( ). Formant : formant : Votrax(, ) LPC(Linear Prediction Coding) : : bit : : REPL(Residual Excited Linear Prediction) vocoder, APC(Adaptivr Predictive Coder) : SC(Sub-band Coder), ATC(Adaptive Transform Coder) 12
13
,, : $30 $ Syntax tree syntax tree (, ), 14
Pattern matching 15
Windows MIDI FM MIDI MIDI 16
(resolution) (KHz) Mac(all type) 8 22 1 Mac(Newer) 16 64 4 Apple IIgs 8 32 / > 70 8( ) PC/Sound Blaster V1 8 13/22 1 PC/Sound Blaster V2 8 15/44.1 1 Atari ST 8 22 1 Atari Falcon 030 16 50 8( ) Amiga 8 29 4( ) Sun Sparc U-LAW 8 1 Sun Sparc St.10 U-LAW, 8, 16 48 1( ) NeXT U-LAW, 8, 16 44.1 1( ) SGI Indigo 8, 16 48 4( ) VAXstation 4000 U-LAW 8 1 DEC 3000/300-500 U-LAW 8 1 17
Self-describing encoding Raw Self-describing.au,.snd.aif(f), AIFF.aif(f), AIFF.iff, IFF/8SVX.voc.wav, WAVE None, HCOM.mod,.nst NeXT, SUN Apple, SGI Apple, SGI Amiga Sound Blaster Microsoft Macintosh Amiga,, encoding,, resolution,,, resolution,, (AIFF ),,,, resolution, (Huffman ) ( ) 18
AIFF(Audio IFF) AIFC Apple SGI AIFC AIFF Snd NeXT Sun SNDSoundStruct, Interface Builder 19
VOC Creative Lab. voice (,, ) ( ) 00H~12H 13H 14H~15H (20 ) 16H~17H 18H~19H ( Create Voice File ) EOF( ) offset number number 2 (byte) 00 Terminator 0 1AH~ 01 Sound data 2 (, ) 02 Sound 03 Silence 3 (silence, ) Silence 04 Maker 2 05 ASCII 06 Repeat 2 07 End repeat 0 08 Extended 20 4 (, )
WAV IBM Microsoft 4 RIFF 4 length 4 WAVE 4 fmt 4 length 2 Format tag WAVE category 0001H=Microsoft PCM 0101H=IBM U-LAW 0102H=IBM A-LAW 0103H=IBM AVC ADPCM 2 channel Wave 1=mono, 2=stereo 4 samples per second 4 bytes per second Wave ( ) 2 bytes per sample 2 bits per channel 4 data 4 length wave n sample wave 21
Real Audio Encoder Netscape real audio real audio real audio real audio player 14.4 : mono AM 14.4 Kbps 28.8 : mono FM 28.8Kbps.wav,.au,.pcm, raw Sound Card CD Sampling resolution.wav 8, 11, 22, 44KHz 8 or 16 bit, mono.au 8, 22, 44KHz Mono.pcm 8, 11, 22, 44KHz 8 or 16 bit, mono 22
MIDI(Musical Instrument Digital Interface) MIDI MIDI, MIDI MIDI MIDI Roland IBM PC MIDI MPU-401 MIDI Roland MPU-401, MPU-IPC-T, LAPS-T CMS CMS-401, CMS-404 Music Quest MQX16, MQX32 MQX 23
MIDI MIDI DIN( ) connector MIDI MIDI connector 5 pin MIDI -1 MIDI-IN ( MIDI IN) MIDI-OUT( OUT) MIDI-THRU(MIDI-IN MIDI -2 MIDI, 3~4 ) MIDI -3 MIDI-OUT MIDI-IN MIDI-THRU MIDI-IN 24
MIDI chain MIDI -1 MIDI-OUT (master) MIDI-IN MIDI -THRU Box (master) THRU THRU MIDI -2 (slave) MIDI-IN MIDI -3 (slave) MIDI-IN MIDI -4 (slave) MIDI-IN 25
MIDI channel 16 channel MIDI protocol master slave master slave MIDI 10 10 2 start stop 8 31.25 Kbaud MIDI broadcast MIDI broadcast MIDI MIDI Status Byte( ) Data Byte( ) 26
MIDI Status Byte(HEX) Data Byte 1 Data Byte 2 8n 0k 0v Note off 9n 0k 0v Note on An 0k 0v Polyponic key pressure ( ) Bn 0c 0v Control change Cn 0p Program change Dn 0v Channel pressure En 0v 0v Pitch changes (, ),. Slave n : - k : (note) - v : (velocity) - c : (controller) - pedal p : - 128 voice 27
MIDI MIDI sequencer MIDI MIDI ( ),,,,,, Sequencer Passport Design Master Tracks Pro(MS-Window ) Dynaware USA Ballade Twelve Tone System Cakewalk Professional 28