1. ÁÖÆļö ´ÜÀ§´Â HzÀÌ´Ù
2. ½ÅÈ£ÀÇ ¼¼±â´Â ÁÖÆļöÀÇ ¼±¸íÇÔÀ» ³ªÅ¸³»±âÀ§ÇØ °¡Àå Áß¿äÇÑ ¿ä¼ÒÁßÀÇ ÇϳªÀÌ´Ù. ¸ðµç              Àü±âÀûÀÎ Àç·á; filters, attenuators, amplifiersµî¿¡¼­´Â ½ÅÈ£ÀÇ ¼¼±â¸¦ 3dB¶Ç´Â ±× ÀÌÇÏ     ·ÎÇϵµ·Ï µÇ¾îÀÖ´Ù. ƯÈ÷ International Consultative Committee for Telephone and Telegraph(CCITT) ¿¡¼­ Á¤ÇÑ network ±ÔÁ¤¿¡ µû¸£¸é 3 dBÀÇ ¼¼±â¸¦ ÁؼöÇϵµ·Ï µÇ¾î ÀÖ´Ù.
3. ¾î¶² ±â°ü(U.S federal Communications Commission)¿¡¼­´Â 20dB±ÔÁ¤À» ÁؼöÇϱ⵵ ÇÑ´Ù.
 

The Bit and Bits per Second

1. Bit ¶õ Binary digitÀÇ ¾àÀڷμ­ Data informationÀÇ °¡Àå ±âº»À̵Ǵ ´ÜÀ§ÀÌ´Ù.
  ƯÈ÷, CCITT, ASCII, ANSI, IBM¿¡¼­ ¸¸µé¾îÁø EBCDICµî¿¡ »ç¿ëµÇ¾îÁø Source codeÀÇ    ±âº»ÀÌ         µÇ¾ú´Ù. 
2. ½Ã°£´ç BitÀÇ Àü¼Û·®Àº Á¤º¸ÀÇ Àü¼Û¼Óµµ´ÜÀ§¸¦ ÁöÁ¤ÇÏ´Â ±âº»À̵ȴÙ.
 

Relating Bit Rate to Bandwidth

1. BitÀÇ ÃÊ´ç Àü¼Û·®Àº ÁÖÆļö¿Í °ÅÀÇ ºñ½ÁÇÏ´Ù.
  ex) (1) 2400bit/secÇÏ¿¡¼­´Â 2400 HzÀÇ ÁÖÆļö¸¦ ¿ä±¸ÇÑ´Ù.
        (2) 1.544Mbit/secÇÏ¿¡¼­´Â 1.544MHzÀÇ ÁÖÆļö¸¦ ¿ä±¸ÇÑ´Ù.
 

Squeezing More Bits per Hz of Bandwidth

1. BitÀÇ Á¤Àǹæ¹ý¿¡µû¶ó Bit/secÀÇ Å©±â¸¦ ´Ã¸±¼ö°¡ ÀÖ´Ù.
  ´ÙÀ½Àº ¸î°¡ÁöÀÇ ¿¹¸¦ µé¾ú´Ù.
   (1) BPSK modulation : °¢°¢ÀÇ º¯È­(transition)¸¶´Ù 1bitÀÌ Àü¼ÛµÈ´Ù.
   (2) QPSK modulation : °¢ º¯È­(transition)¸¶´Ù 2bit°¡ Àü¼ÛµÈ´Ù.
                         * 2400 bit/secÀÇ modem¿¡ »ç¿ëµÈ´Ù. »ç¿ëµÇ´ÂmodulationÀÇ ¾çÀº 1200baudÀÌ´Ù.
   (3) 8-ary PSK modulation : 3bit°¡ °¢°¢ÀÇ transition¸¶´Ù Àü¼ÛµÈ´Ù.
                             *4800bit/sec modem¿¡ »ç¿ëµÇ°í modulationdÀÇ ¾çÀº1600baudÀÌ´Ù.
   (4) ±×¿ÜÀÇ ´Ù¸¥ °Í : 4bitÀÇ Àü¼Û(°¢°¢ÀÇ transition¸¶´Ù)
                      9600 bit/sec modem¿¡ »ç¿ëµÈ´Ù. modulationÀÇ ¾çÀº 2400baudÀÌ´Ù.
2. ¶ÇÇÑ, ÀÌÁø¼ö(0, 1)ÀÇ baseband waveform¿¡µû¶ó ´Þ¶óÁö±âµµ ÇÑ´Ù.
   (1) RZ(return-to zero)
   (2) NRZ(non-return-to-zero)
      ex) 6¹øÀÇ º¯È­°¡ ÇÊ¿äÇÑ NRZ¿¡ºñÇØ RZ¿¡¼­´Â 22¹øÀÇ transitionÀÌ ÇÊ¿äÇÏ´Ù.
3. ÃÖ±Ùµé¾î 3°¡ÁöÀÇ Æ¯º°ÇѺо߿¡ À§ÀÇ ¹æ¹ýÀ» ÀÌ¿ëÇÏ°í ÀÖ´Ù.
   (1) Voice channel
   (2) Subscriber loop
   (3) Digital line-of Sight Microwave
 

The Converse of Bit Packing

1. bitÀÇ ¾çÀ» Áõ°¡½ÃÅ°´Â ¹æ¹ý°ú´Â´Þ¸® spectrumÀ» ´Ã¸²À¸·Î½á °°Àº È¿°ú¸¦ º¼¼öµµ ÀÖ´Ù.
   ex) 1kbit/secÀÇ dataÀü¼Û¿¡¼­´Â 1 ¶Ç´Â 2kHzÀÇ ÁÖÆļö°¡ ÇÊ¿äÇÏ´Ù.
       ÀÌ ÁÖÆļö¸¦ 2MHz·Î ´Ã¸°´Ù¸é, dataÀÇ ¾çÀº ´Ã¾î³­´Ù.
2. ÀÌ·¯ÇÑ spread spectrum modulationÀº ¹«¼±ÀüÈ­, PCSµî¿¡¼­ÀÇ ÀâÀ½À̳ª °úºÎÇÏÅëÈ­¿¡¼­     »ý±â´Â  ¹®Á¦Á¡À» ÇØ°áÇÏ´Â ÀåÁ¡ÀÌÀÖ°í, ¶ÇÇÑ »ç¿ëÀÚÀÇ ÁÖÆļö ´ë¿ªÆøÀ» ¾à 15¹è°¡±îÀÌ      ´Ã·ÁÁÖ´Â ÀåÁ¡µµ  ÀÖ´Ù.