4章 ディジタル変調 - ieice-hbkb.org

1 4 1 4 4 - 1 4 [2008 12 ] SN 4-1 4-2 4-3 4-4 OFDM 4-5 2010 1/(11) 4 1 4 4 - 1 - 4 4-1 [2008 12 ] fc 4-1-1 1) a(t) R(t) cos (2 fct (t)) 4 1 R(t) (t) R(t) (t) a(t) fc a(t) uI(t)cos2 fct uQ(t)sin2 fct 4 2 uI(t) R(t)cos (t) uQ(t) R(t)sin (t) uI(t) uQ(t) I Q 2) a(t) uI(t)cos2 fct uQ(t)sin2 fctuI(t)

2 Cos2 fctuQ(t) sin 2 fct 4 1 ))()((212sin)(2cos)()2sin)(2cos)(()(2222 2222tututftutftutftutftutaQIcQcIcQcI+=+= = 4 3 2010 2/(11) 4 1 4 4-1-2 4 1 Re }))()(Re{()(2tfjQIcetjututa += 4 4 Re{ } u(t) uI(t) juQ(t) e j2 fc t (4 4) (u(t)ej2 fct u* (t)e j2 fct) /2 a(t) ))()((21)(ccffUffUfA + = 4 5 U( f ) u(t) uI(t) uQ(t) UI( f ) UQ( f ) U( f ) UI( f ) jUQ( f ) 4 6 1) A( f ) U( f fc) / 2 U*( f fc) /2U( f)U( f) H( f)B( f ) H( f fc) U(f fc) /2 H( f fc)U*( f fc) /2H( f)G( f ) H( f fc) H*( f fc)(a ) (b) 4 2 )()()()()(22222tututututuQIQI+=+= 4 7 (4 3) 2 1) 1970.

3 2) 1994. 2010 3/(11) 4 1 4 4 - 1 - 4 4-2 [2008 12 ] 4-2-1 1) {}2)/)(2/2(logexp)(BfAfH = 4 8 B 3 dB B 4-2-2 T 1/T 2) Sinc ++ + =TfTfTTfTTTfTfH2)1(02)1(2)1(21cos122)1(0 )( f 4 9 0 1 1 2) 1) 1994.

4 2) Proakis, Digital Communications, 4th ed., McGraw-Hill, 2001. 2010 4/(11) 4 1 4 4 - 1 - 4 4-3 [2008 12 ] 4-1 sI(t) sQ(t) sI(t) sQ(t) IQ 4-3-1 (1) 4 3 1) 1) 4 3 (2) ASK Amplitude Shift Keying QAM Quadrature Amplitude Modulation ASK sI(t) 2 ASK OOK OnOff Keying 4 4(a)

5 1 QAM ASK sI(t) sQ(t) 16 QAM 16 QAM sI(t) sQ(t) 4 4 4(b) A 1/ 10 16 ASK 2 ASK QAM 4 3 2010 5/(11) 4 1 4 2 a K b 16 QAM 4 4 OOK 16 QAM (3) PSK Phase Shift Keying PSK ASK QAM 360 3 5(a)(b) 2 PSK BPSK 180 , 4 PSK QPSK 90 1 1 11 11 5 PSK PSK 3 5(a)(b) 1 0 0 1 3 5(c) /4 QPSK2) 4 4 45 2010 6/(11) 4 1 4 (4) FSK Frequency Shift Keying FSK PSK CPFSK Continuous Phase FSK PSK 2 FSK 0 90 FSK MSK Minimum Shift Keying 3 6(a) MSK 3 6(b) MSK 3 6(b) GMSK Gaussian-filtered MSK 3)

6 GMSK 4 6 MSK MSK, GMSK MSK GMSK MSK 1) GMSK 4-3-2 4 7 BPSK, QPSK, GMSK 3), 16 QAM4) Eb/N0 1 erfc 2010 7/(11) 4 1 4 4 7 1) 1996 2) Y. Akaiwa, Introduction to Digital Mobile Communications, John Wiley and Sons, 1997. 3) K. Murota and K. Hirade, GMSK Modulation for Digital Mobile Radio Telephony, IEEE , , , , July. 1981. 4) 1998 2010 8/(11) 4 1 4 4 - 1 - 4 4-4 [2008 12 ] 1) 4-4-1 DS Direct Sequence 1) 1 B W W/B 4 8 LPF 4 8 4 8 PN Gold 1) Walsh-Hadamard 2)

7 PN 4-4-2 FH: Frequency Hopping 1) FH FFH: Fast FH FH SFH: Slow FH 1) 1998. 2) J. G. Proakis, Digital Communications, 4th ed., McGraw-Hill, 2001. 2010 9/(11) 4 1 4 4 - 1 - 4 4-5 OFDM [2008 12 ] OFDM Orthogonal Ferquency Division Multiplexing 4-5-1 FFT OFDM T 1/T FFT/IFFT 4 9 1) 4 9 OFDM 4-5-2 4 9 FFT IFFT FFT 4 10 1) 4 10 4 10(a)

8 IFFT 2010 10/(11) 4 1 4 2010 11/(11) 4 10(b) FFT FFT FFT FFT T OFDM 4-5-3 OFDM 2) (1) (2) OFDM (3) PTS Partial Transmit Sequence SLM Selective Mapping PTS SLM PTS SLM SLM PTS 1)

9 Proakis, Digital Communications, 4th ed., McGraw-Hill, 2001. 2) Han and Lee, An Overview of Peak-to-average Power Ratio Reduction Techniques for Multicarrier Transmission, IEEE Wireless Commun., , , , April. 2005.