?????????? ????????????????? ??????? (?)

???????????????? texual imformation ?????????????? formatting ??????????????? ??????????????
Texual messages(texual data) ?? ??????? ????????????????????? alphanumeric characters ??? sequence ???????? ????????? ???????????????? transmitted ????????????? ????????? character ??? sequence of bits ???? encoded ?????????? ? ???????????? bit stream or baseband signal ???????????? ? finite symbol set ???????????? M = 2^k ??? k ?bits ??? ???????????? ?????????????? ???????????????? symbols ??????????????? ???????????????????? ?????? ??????? ??????????????????????? M symbol set size ??????? ??????? M- array system ???????????? ? ??????????????????????????? ??????????? k ??? M ??? ????????? ?????????????? k=1 ??????????? M=2 ???????????? ????????? ???????? ????????????????? ???? ??????????????? waveform ??????????????? ???????????? modulator ?? 1 ?????????????????? waveforms 2 ???????????? ?????????????????????????? waveform ?????? 0 ??? ????????????? k= 2 ??????????? M=4 ???????????? ????????? quateranry (????) 4-ary ????????????? symbol time ???????? modulator ?? waveforms ???????? symbol ??? ?????????????? ???????? ?????????????? ?? bits ??? sequence ??? ???????????????????????? ASCII code ?????????????????????? texual message ??? bit sequence ?????? ??????????? ??? ??? ??????????? ????????????????? M ? ???????????????? ????????????? ?????????????? binary digits ?????????????? ????????? 8-ary digits ??? ??????????? ??????????? ????????????? k=logM(log ??? base ? 2 ??) ??????????? k ?????????? ????????? k ????????? bit ?????????????? ????????????????????????????? ?????????????



???? --
Texual message ??? THINK ?????????? ?????????? ????????? ?????????????????
6-bit ASCII character coding ??? ??????? ? (??????? ASCII table ??????????????????) T ?????? ????????????? ? bit ???????? 6 ??????????? THINK ? 5 ??????????? 6*5=30 ????? ????????????? THINK ?????? ??????????? ??????????????30 ??????????? ????????? k ??? M ?????????? ???????????????????? M ??? 8-ary digit ????????????????? k=logM(log ??? base ????? 2 ??) ?? k ????????? 3 ????????????????? ?????? ????? 30 ??? k=3 ?????????????????? 10 ?????? ??????? ???? ?? ???? transmitted ???????? 10 octal symbols ??? ????????????????? transmitter ??? ?????????????????? symbols ?????? ??????????????? waveforms s_i(t) ( i=1,?..,8 ) 8 ?? ??? ??? (set) ???????? symbol time ?????????????? ???? ?????????????????? symbols ?????? symbol ???????? transmit ??????????????? ?????? ?????????? ??? THINK ?????? message ??? ?????????????? 8-ary modulating systme ?????????? waveforms ?? ????????????????????
????? ???? ??????
Texual message ? HOW ?????????
6 bit ASCII code ??????????????? character ??????????? bit sequence ??? ???????????? ?
4-ary digits ?????????????????????? ???????? k ????????? k=logM(base ????? 2)= 2 ????????? ? symbols ?????? 9 ????????? ???? symbol 9 ???? transmitted ??????? quateranry symbols ????????????? ???? transmitter ??? ?????????????????? symbols ?????? ??????????????? waveforms s_i(t) ( i=1,?..,4 ) 8 ?? ??? ??? (set) ???????? symbol time ?????????????? ???? ?????????????????? symbols ?????? symbol ???????? transmit ??????????????? ?????? ?????????? ??? HOW ?????? message ??? ?????????????? 4-ary modulating system ?????????? waveforms 9 ????????????????????



?? ????? ?????????? LOVE ?????? ???????? ??? ????????????????? ????


????????? ????????? log ??? base ????????? ???????????? ????????????????????? ??????????????

?????????? ?????????? ??????? ??????? (?)

?????????????? ??????????????? imformation signal ?????? ?????????????????? ????????????????? ???????? ????????? ???????????? ?????????? ???????????? signal ?????? ?????????? ?????????????? ??????? signal processing ????????????? signal processing ????? analog signal processing ??? digital signal processing processing(DSP) ??????????? ?????????????????? ??? ?????????????? DCS ??? ??????????? ???????????? DSP ???????????? ????? ?????????

Formatting

Formatting ?? signal processing ??? ????????????????? ?????? ???? ???????????????? ????????????? ?????? signal?????? ?????????? message ???????????????????????? ?????? signal ??? digital imformation, texual imformation, analog imformation ??????????????? formatting ??? ???????? ??????????????? character coding (formatting texual data), sampling, quantization, pulse code modulation (PCM) ??????????????

Digital imformation ????? formatting ????????????????? texual imformation ??????? coder ??????????????????????? ????????????????????? ?????????????analog imformation ??????? ????????? sampling ???????? ???????? quantization ?????????? ????????????? encode ?????????? formatting ????????????????????? ?????? ???????? ?????? sequence ???????????????? ??????????? ???????????????????? baseband channel (?????????? coaxial cable ) ???????????? ?????????????????? ??????????????? ???????? ?????? baseband channel ????? waveform ???????? ????? ???????? ????????????? ??????????? ?????????????????????? waveform ????????? ?????????????? Baseband channel ????????????? waveform ????? pulses ????????

????????????????? pulse modulator ????? pulse waveform ????????????????? ?????????????????????? baseband channel ???????? ????????????????? ???????????? baseband channel ??????????????? receiver ????????????? pulse waveform ??? demodulate ??????????????? ???????? ???? pulse waveform ??? ?????????????? ????????????????? ?????? ??????? ????????( detect) ?????? ???????????? formatting ??? ??????????? ????????????????? ?????? imformation signal ????????????????????

Formatting texual Data (character coding)

????????????? ?????????? ??????? ???????????????????? ?????????? ??????????????????? texual ????? ????????????? ?????????????? ???????????? ????????? ?????????? ????????????????????? texual data ?????????? a,b,c? ???????????? ????????? ???????????? hi, do, you, love, me ?????????? ???? ??????????? ????????? standard format ?????????? ???????????????????? encode ?????????? standard format ???????? ASCII,EBCDIC,Baudot ?????????????? character coding ?????????????? ???????????? ASCII format ??????????????????????????

????????? texual imformation ??? ?????? formatting ???????????????? ?????????????????? ????????????

?????????? ?????????? ??????? ??????? (?)

???????? ????????????? ???????????? ????????? ?????????? Digital communication ?????????? ?????????????? ??? ??????????? ???????? ???????? ??????? ????????? ?????????????? ?????? ?????? ???????????? ??????? ?????????????? Analog - ?????????????????? ?????????? ????????????????? ??????????? ???????? ???????????????? ????????????? ???????? ???????? ??????????????????? ??????? ?????????????????? ???????????????? ???? ??????? ?????????????????? ???????? ?????????? ??????????? ??????????????? ???????? ????????????(distortion) ? ?????????? ?????? ???????? ??????????????? (interference) ?????? ???????????? ??????????????? ?????????? ??????????? ?????????? ?????????????? ????????? ???????????????? ????? ?????????????? ???????????????????? ?????????????????????? ???????? ?????? ?????????? ????????????????????????? ??????????? ???????????????

DCS ??? ????????? ????????? ????? ????????? (imformation) ??? ?????????????????? (bits) ????????????????????????? process ??? formatting ????????????????? process ????????? bits ?????? ????????????????? digital messages (????) message symbols ????????? ????????????? ????? ?????? message symbol m_i(i=1..M)?????????? M member ?????????????? ??????? alphabet ??????????? ??????????? ??????????????????[????? m-i ???????????????????????? ?????????????????????????????????????????????? ?????????????? ??????????????? ???????????????????????????] ???????????? M ? ? ???????????????? message symbol ?? ???????????????? (????????????? ???? message symbol ??? bit ??????????????????????????? ???????? M ?? ? ???????????????????? symbol ????? bit ???????? ? ??????? ????????????????????? channel code (error correction code) ?????????????? ????????????????? ?????? ????? message symbols ?????? sequence ??? channel symbols ?????? sequence ????? ?????????????? ???????????? ???????????????? ????????? bits ?????????? ???????????? ?????????? transmission channel ????????????????????? ??????????? transmission channel ???????????????? modulation ??????????? pulse modulation ????? ??????????????? ( voltage level 0 or 1) ??? ???????? ??????? baseband waveform ???????????????????????? baseband waveform ????? spectrum ??????? frequency 0 Hz ????????? ???????????MHz ????????? signal ??????????????????? RF transmision ?????????????? ?????????????? bandpass modulation ?????????????? transmission medium (channel,etc) ? pulse-like waveform??? ???????????????? ?????????????????????????? bandpass modulation ??????????? ?????????????medium( channel ) ?? bandpass waveform ????????????????? bandpass ??? frequency spectrum ?? baseband frequency spectrum ????????????? source coding ????? ???????????? ?????????? (A/D) ??? ?????????????????? ?????????? ????????????????? ??? ??????????????? Encrypt ????? ????????????????? ??????????????? ???????????????? ???????? ???????????????????? ?????????????????? ????????? ?????????????????? channel coding ?????????????? ???? rate ????????? ?????????????????? ????? (probability of error) ??? ?????????????? multiplexing ??? multiple-access ????? ???????? source ?????? ?????????????????? signals ?????? ??????????????? ???????????? ?? communications resource (spectrum,time ) ??? ?????????????? ???????????????????? frequency spread ????? ???? ???????????????? ??????? ??????????????????? ????????????? signal ??? ???????????? ?????????? ??????? ??????????? ??????????????? ?????????????? source coding , encrypt, channel coding, multiplexing and multiple-access ???????? ?????????????????????????? ??????????
Reciver ?????????????? transmitter ?????????? ?????????????????? bandpass waveform ??? demodulator ??? baseband waveform ?????????????????????????detection ????? ?????? baseband waveform ??? binary bit ?????? ??????? ????????????? ?????????????????????????????????????? DCS ????????????????????????????????? DCS ??????????????? ?????? ?????????? ?????????????? ????????????????????????