1장 통신 이론의 기본 사항

1 1 : : : : o : o : : , , : o : o : ( ) - : 1) 2) o : : o : o : o : o : o - : (random) - : - : (non-linear) : o : o : (LNA, Low Noise Amplifier) o : o : o : o : o : f( ) ( )=v( ) o : v=1 0 0=c( , 3 108m/s).

2 ( , permittivity) ( , permeability) ( , conductivity) o : 800 MHz ( )=c( )f( )=3 108m/s800 106Hz= : : o : 800 MHz o (PCS) : 1800 MHz : (spectrum) : : o kHz, MHz, GHz, THz, PHz k(kilo), M(mega), G(giga), T(tera), P(peta) 103, 106, 109, 1012, 1015 o mm, m, nm, pm, fm m(milli), (micro), n(nano), p(pico), f(femto) 10-3, 10-6, 10-9,10-12, 10-15 JCS VHF Band100 MHz-300 MHzUHF o AM : (9kHz 120 ( 531 KHz 1602kHz 9 KHz ) o FM : 88 MHz 108 MHz 200kHz 100 ( 200kHz ) o TV : - 2 13 VHF 54 MHz 216 MHz 6 MHz - 14 83 UHF 470 MHz 890 MHz 6 MHz o : 800 MHz (824-849 MHz/869-894 MHz) o (PCS).)

3 1,800 MHz (1,750-1,780 MHz/1,840-1,870 MHz) o IMT- 2000 : 2 GHz 230 MHz(1,885-2,025 MHz/2,100-2,200 MHz) : : o o - : 3kHz - TV : 30 6 MHz : o : 1 0 (bit) o : bps(bits per second)( ) Shannon (Channel Capacity) : C = BW log2(1+SN) o C : Capacity , bps o BW : Bandwidth Hz o S/N.

4 Signal to Noise ratio 1(W) (W) 10kHz C = 10,000(Hz) log2(1+1(W) (W))=43,923bps 1(W) (W) 100kHz 10 ( 10 )C = 100,000(Hz) log2(1+1(W) (W))=439,231bps 10 10(W) 10 (W) 10kHz ( 10 )C = 10,000(Hz) log2(1+10(W) (W))=76,511bps (log) 1(W) (W) 1 Mbps BW = C log2(1+SN)=100,000(bps)log2(1+1(W) (W))=22,767Hz 23kHz o : (S/N) o : BER(Bit Error Rate) ( ) -1000 1 BER 10-3 BER : BER ( 1(W) 2(W) vs (W) (W) ) Eb/N0 : Shannon : Eb/N0 -> ( (dB)).

5 ( )