频谱分析仪和矢量信号分析仪

DELAY:-1.318ms FREQ:862.126 600MHz
TIME SPAN:1.9ms
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GATE
time
Frequency
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DUT
RF in
IF
CRT Display
DUT
LO
TG out
Tracking Adjust
Tracking Generator
• 2cos(ѡct) 2cos(ѡct-90) . • E(t)=I(t)cos(ѡct)+Q(t)cos(ѡct-90) • E(t)*2cos(ѡct)=2I(t)cos(ѡct) cos(ѡct) +2Q(t)cos(ѡct-90) cos(ѡct) = 2[I(t)/2]cos(ѡct-ѡct)+2[I(t)/2]cos(ѡct+ѡct) + 2[Q(t)/2]cos(ѡct- ѡct +90)+2[Q(t)/2]cos(ѡct+ѡct -90) = I(t)+ I(t)cos(2ѡct)+ Q(t)cos(2ѡct -90) • I(t)cos(2ѡct) I(t).
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QPSK 相位域
A B C D
Serial/Parallel Conversion DiBits
I(t) A B C D Q(t) Symbol rate fBit 2
1 2 3 4 5 6 7 t Bit rate, Data rate fBit
Q
Bit Sequence 1. 2. 0 1 1 0 0 0 1 1 Dibits I Q 0 1 1 0 0 0 1 1 Transmitted Phase 45º 135º 225º 315º (D) (A) (C) (B)
Anritsu Basic Training Material
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…
2
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•
(FFT)
(
)
A
f1
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f2
f
4
A
f1
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f2
f
5
•
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•
, dBc 0 , -dBc
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Amplitude Modulation
UMod(t) = UC(t) . cos(wC(t).t + FC(t))
AM Time Domain UC Umax
ÛC
Frequency Domain ÛC UC
m Û 2 C m Û 2 C
Phase Domain UAM
Mixer Level(dBm)
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• • • • •
RBW VBW
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•
(
)RBW
3 dB 3 dB BW
Mixer
LO
/ (RBW)
RBW
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•
RBW
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•
RBW
10 kHz RBW 3 dB
0 - 5 - 10 - 15 - 20 - 25 - 30 - 35 - 40 - 45 - 50
RLV:- 54.1dBm
AT 15dB# TS 1.9ms
RBt 10kHz# VBt 30kHz# POWER
T:SMP
POWER(dBm):- 67.08dBm POWER(W) :196pW
“10” “0” 90º “00”
“1” 180º
“0” 0º
I
“11”
“01”
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QPSK - Modulator
I-Channel
Q RF-In I
0/180°
0°
S
90°
0/180°
RF-Out
Q-Channel


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• – – • • – – – – –
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• •
– – – AM,FM,PM, Pulse I Q / TDMA CDMA
•
• •
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“
EMod(t) = EC(t) . cos(wC(t).t + FC(t))
AM FM FM
-20
RBW=10KHz
.
-40
TOI
RBW=1KHz
-60 -80
-100 -60 -30 0 +30
(dBm)=
(dB)
(dBm)confidential
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Fra Baidu bibliotek •
-105 -107 DISTORTION, dBc -109
-111
Potential Dynamic Range
-113 -115 -90 -60 -30 0
AM
FM
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BPSK
Multiplier as BPSK modulator
Q
F = 180°
F = 0° I
UC
UBPSK
UData
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BPSK 时域和频域
0
1
0
Û
U TBit t
- fBit
fC fBit
+ fBit
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BPSK, 1 Mbps (unfiltered)
f
ÛC
M = Df / fmod
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Vector modulation
• • IQ I(t) , • E(t)=I(t)cos(ѡct)+Q(t)cos(ѡct-90) = I(t)cos(ѡct)+Q(t)sin(ѡct) ={[I(t)]2+Q[t]2}1/2cos(ѡct-TAN-1(Q(t)/I(t)) cos(ѡct) , Q(t) cos(ѡct-90)
)/(RBW
)
100 kHz RBW
10 dB
10 dB
10 kHz RBW
1 kHz RBW
RBW =
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(VBW)
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/
100kHz

:-123.77dBc/Hz
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50kHz , , 100 kHz
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Angle Modulation
UMod(t) = UC(t) . cos(wC(t).t + FC(t))
f(t) = d F(t) / dt
FM Time Domain Frequency Domain ÛC t fC f
F
FM Phase Domain
+DFC -DFC f + D fC fC - D fC
Filtering
Unfiltered
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Filtered
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EVM
EVM? Error Vector Magnitude(EVM) ,
EVM
EVM EVM
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m
• : E(t)=[1+mcos(ѡmt)]cos(ѡct) • m=(Ec-Emin)/Ec=(Emax-Ec)/Ec=(Emax-Emin)/(Emax+Emin) • : m/2=Esb/Ec • log m – log 2 = log Esb – log Ec • m(dB)= -[Ec(dB)-Esb(dB)-6dB]
10 kHz
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•
RBW
RBW = 1 kHz
RBW = 10 kHz
3 dB
7.5 kHz
60 dB
60 dB BW = 15 kHz 10 kHz 10 kHz
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•
RBW
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•
RBW
(dB) = 10 log(RBW
m Û 2 C m Û 2 C
Umin

fC ÛC
m = UC / ÛC = (Umax - Umin) / 2 • ÛC
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Angle Modulation
• • • • frequency modulation (FM) and phase modulation (ØM) 都是角度调制 频率：Ѡ(t)=d[ϕ(t)]/dt, 相角：ϕ(t)=∫ Ѡ(t)dt Ѡ(t)= Ѡc+ ΔѠpk f(t) E(t)=cos[ѡct+(Δ Ѡ pk/ Ѡ m)sin Ѡmt] =J0(β)cos Ѡct-J1(β)[cos(Ѡc-Ѡm)t+ cos(Ѡc+Ѡm)t]-J2(β) )[cos(Ѡc-2Ѡm)t+ cos(Ѡc+2Ѡm)t]-J3(β) )[cos(Ѡc3Ѡm)t+ cos(Ѡc+3Ѡm)t]-…… • 调制指数：β = Δ Ѡ pk/ Ѡ m
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Conventional Modulation
Keying
Digital Modulation
AM
0
1
0
1
0
0
1
FM
0
1
0
1
0
0
1
ASK U
PSK U t 0 1 0 1 0 0 1
FM
UMod(t) = UC(t) . cos(wC(t).t + FC(t))
FM
FSK U t

: -69.86dBm/ch
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2
X
N dB
99
3dB

: 246.4 kHz
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ACPR

: L1:-70.74 U1:-70.74 L2:-78.47 U2:-78.31
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-13.52dBm
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时间域
频率域
相位域
ÛC
ÛC UC UC f t fC
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Amplitude Modulation
• [1+mcos(ѡmt)] Acos(ѡct) =
• E(t)=[1+mcos(ѡmt)]cos(ѡct) cos(ѡct)+(m/2)cos(ѡct-ѡmt)+(m/2)cos(ѡct+ѡmt) • cos(ѡct-ѡmt) cos(ѡct+ѡmt) ѡm • cos(ѡct) • <1/3