acprcalc.pdf
Transcript of acprcalc.pdf
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f ACPRBW Lower Band Ed e for ACPR Measurement
______________________________________ Initial Calculations
ACPR RequirementsACPR 30_30spec 45dBC:=Synthesis Inpu ts
3rd Order Intercept Point
IP3 50dBm:=Analysis Inpu ts
Bandwidth for ACPR Measurementf ACPRBW 30kHz:=
Offset of Center Frequency for ACPR Measuref off 885kHz:=
Output Center Frequencyf 0 0MHz:=
Bandwidth of Transmitted SignalBW 1.228MHz:=
5th Order Intercept PointIP5 45dBm:=
Output Power Pout 28dBm:=
______________________________________ Inputs
______________________________________ Table of ContentsI. Inputs
II. Initial Calculations
III. Power Density CalculationsIV. ACPR Calculations
V. IP3 Estimation
VI. Example
VII. Measurement Procedure
VIII. ACPR Specifications
IX. Comparison to Measured Results
X. References
XI. Copyright Notice
Constants
Units
useful functions and identities
ACPR Calculations
for Power Amplifiers
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f 1 f 0 f off +
2−:=
Upper Band Edge for ACPR Measurementf 2 f 0 f off +
f ACPRBW
2+:=
P0 10
Pout
10:= P0 630.957mW
mW= Output Power
BBW
2:= Half Bandwidth
______________________________________ Power Density Calculations
Power Densi ty due to both 3rd and 5th Order Distor t ion
P IP3 IP5, Pout, B, f 0, f ,( ) P0 10
Pout
10←
1
2 B⋅P0 6 P0
2⋅ 10
IP3−
10⋅− 30 P03⋅ 10
IP5−
5⋅−
9 P03⋅ 10
IP3−
5⋅ 90 P04⋅ 10
IP3−
10
IP5
5−⋅++
...
225 P05⋅ 10
2−IP5
5⋅
⋅+
...
⋅
1
8 B3⋅
6 P03⋅ 10
IP3−
5⋅ 120 P04⋅ 10
IP3−
10
IP5
5−
⋅+ 150 P05⋅ 10
2−IP5
5⋅
⋅+
⋅ 3 B2⋅ f f 0−( )
2−⋅+
...
10
32
P05
B5
⋅ 10
2−IP5
5⋅
⋅ 3 5 B2⋅ f f 0−( )
2−2
⋅ 40 B4⋅+
⋅+
...
Φ⋅
6 P03⋅ 10
IP3−
5⋅ 120 P04⋅ 10
IP3−
10
IP5
5−
⋅+ 150 P05⋅ 10
2−IP5
5⋅
⋅+
1
16B3
⋅ 3 B⋅ f f 0−( )− 2⋅
10
16
P05
B5
⋅ 10
2−IP5
5⋅
⋅ 2 B⋅ 4 B⋅ f f 0−( )− 3⋅ 2 B3⋅ 4 B⋅ f f 0−−( )⋅+ 3 B⋅ f f 0−−( )
4−⋅+
...
+
5
32
P05
B5
⋅ 10
2−IP5
5⋅
⋅ 5 B⋅ f f 0−−( )4⋅
Φ 5 B⋅ f f 0−−( )⋅ Φ f f 0− 3 B⋅−( )⋅+
:=
Power Densi ty due to 3rd Order Distor tion Alon e
If the output power is 5 to 10dB lower than it's 1dB compression point, the following equation may be used.
P3rd IP3 Pout, B, f 0, f ,( ) P0 10
Pout
10←:=
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1
2 B⋅P0 6 P0
2⋅ 10
IP3−
10⋅− 9 P02⋅ 10
IP3−
5⋅+
⋅3
4P0
3⋅ 10
IP3−
5⋅1
B3
⋅ 3 B2⋅ f f 0−( )
2−⋅+
Φ B −(⋅
3
8P0
3⋅ 10
IP3−
5⋅1
B3
⋅ 3 B⋅ f f 0−−( )2⋅ Φ 3B f f 0−−( )⋅ Φ f f 0− B−( )⋅+
______________________________________ ACPR Calculations
There are two ways of measuring ACPR. The first way is by finding 10*log of the ratio of the total output
power to the power in adjacent channel. This is call ACPR 1250_30 below. The second (and much more popular
method) is to find the ratio of the output power in a smaller bandwidth around the center of carrier to the power in the
adjacent channel. The smaller bandwidth is equal to the bandwidth of the adjacent channel signal. This is called
ACPR 30_30 below. ACPR 30_30 is more popular, because it can be measured easily as indicated in the measurement
procedure section.
ACPR Due to bo th 3rd and 5th Order Distor t ion
PIM35 IP3 Pout, B, f ACPRBW, f off ,( ) 10 log
f 0 f off +f ACPRBW
2−
f 0 f off +f ACPRBW
2+
f P IP3 IP5, Pout, B, f 0, f ,( )
⌠ ⌡
d
⋅:=
PIM35 IP3 Pout, B, f ACPRBW, f off ,( ) 25.622− dB=
ACPR 1250_30 IP3 Pout, B, f ACPRBW, f off ,( ) Pout PIM35 IP3 Pout, B, f ACPRBW, f off ,( )−:=
ACPR 1250_30 IP3 Pout, B, f ACPRBW, f off ,( ) 53=
ACPR 30_30 IP3 Pout, B, f ACPRBW, f off ,( ) Pout 10 logBW
f ACPRBW
⋅− PIM35 IP3 Pout, B, f ACPRBW, f off ,( )−:=
ACPR 30_30 IP3 Pout, B, f ACPRBW, f off ,( ) 37.50=
ACPR Du e to 3rd Order Distor t ion A lone
PIM3 IP3 Pout, B, f ACPRBW, f off ,( ) 10 log1
810
3 Pout⋅ 2 IP3⋅−
10⋅1
B3
⋅ 3 B⋅ f off
f ACPRBW
2−−
3
3 B⋅ f off
f ACPRB
2+−
−
⋅
⋅:=
PIM3 IP3 Pout, B, f ACPRBW, f off ,( ) 29.515− dB=
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4 3 2 1 0 1 2 3 4150
100
50
0
50
10 log P IP3 IP5, Pout, B, f 0, f i,( ) MHz⋅( )⋅
10 log P3rd IP3 Pout, B, f 0, f i,( ) MHz⋅( )⋅
f i f 0−
10 log P IP3 IP5, Pout, B, f 0, f 0,( ) BW⋅( )⋅ 27.783dBm=
f i
f 0 N bw B⋅−i 1−
num 1−2⋅ N bw⋅ B⋅+:=
Number of Bandwidths for Plotting N bw 5:=
Index Vector for Plottingi 1 num..:=
Number of Points for Plottingnum 500:=
______________________________________ Example
IP3find ACPR 30_30spec Pout, B, f ACPRBW, f off ,( ) 48.678dBm=
IP3find ACPR 30_30 Pout, B, f ACPRBW, f off ,( ) 5− log
10
ACPR 30_30 4 Pout⋅−
10 B4
f ACPRBW
⋅
3 B⋅ f off
f ACPRBW
2−−
3
3 B⋅ f off
f ACPRBW
2+−
3
−
⋅ 2+:=
______________________________________ IP3 Estimation
ACPR 30_30 IP3 Pout, B, f ACPRBW, f off ,( ) 41.39=
ACPR 30_30 IP3 Pout, B, f ACPRBW, f off ,( ) Pout 10 logBW
f ACPRBW
⋅− PIM 3 IP3 Pout, B, f ACPRBW, f off ,( )−:=
ACPR 1250_30 IP3 Pout, B, f ACPRBW, f off ,( ) 57=
ACPR 1250_30 IP3 Pout, B, f ACPRBW, f off ,( ) Pout PIM3 IP3 Pout, B, f ACPRBW, f off ,( )−:=
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f off 885kHz:= Worst Case=900kHz-30kHz/2
ACPR 30_30spec 54dBC−:=
f off 1980kHz:= Best Case=1980kHz-30kHz/2
Peak_ave 3dB:=
Vddmin 3.5V:= Vddmax 4.8V:= Supply Voltage
PAEmin 35%:= Minimum Power Added Efficiency at Maximum Power
PAEmin 20%:= PAE with Power 15-20dB Below Maximum Power (Use to spec Iq)
DR 80dB:= Dynamic Range (Gain must also be linear over this range)
VSWR max10
1:= Must be stable into a 10:1 VSWR for all phases
Noise := Noise floor in receive band must be below
Cost := Competitive Cost must be below
IS-54/IS-136 Handset Specific ations
Pout 10 log1mW
⋅:= Pout dBm=Pout
f 0min 824MHz:= f 0max 849MHz:=
BW 24kHz:=
MHz
______________________________________ Measurement Procedure
Quick Method: Set Resolution measurement bandwidth to 30kHz. Put one marker at center of transmit band
and another marker at 885kHz offset. The delta is the 30kHz-30kHz ACPR measurement. Add
10*log(1.25MHz/30kHz) for the 1.25MHz-30kHz ACPR measurement.
______________________________________ ACPR Specifications
IS-95 CDMA Base Station Specif ication s
Pout 10 log18W
1mW
⋅:= Pout 42.553dBm=
f 0min 864MHz:= f 0max 894MHz:=
BW 19.2kHz 64⋅:= BW 1.229MHz=f ACPRBW 30kHz:=
ACPR 30_30spec 45dBC:=
f off 765kHz:= Worst Case=750kHz+30kHz/2
f off 1975kHz:= Best Case=1980kHz-30kHz/2
Peak_ave 10dB:=
IS-95 CDMA Handset Specif ications
Poutmin 27dBm:= Poutmax 30dBm:= Linear Power at Load
f 0min 824MHz:= f 0max 849MHz:=
BW 19.2kHz 64⋅:= BW 1.229MHz=f ACPRBW 30kHz:=
ACPR 30_30spec 42dBC−:=
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All software and other materials included in this document are protected by copyright, and are owned or
controlled by Circuit Sage.
The routines are protected by copyright as a collective work and/or compilation, pursuant to federal copyright
laws, international conventions, and other copyright laws. Any reproduction, modification, publication, transmission,
transfer, sale, distribution, performance, display or exploitation of any of the routines, whether in whole or in part,
without the express written permission of Circuit Sage is prohibited.
______________________________________ Copyright Information
______________________________________ References"Linear and Rf Power Amplifier Design for CDMA Signals: A Spectrum Analysis Approach," by Qiang Wu, Heng
Xiao and Fu Li, Microwave Journal , December 1998, pp. 22-40
"Power Amplifier Spectral Regrowth for Digital Cellular and PCS Applications," Kennedy et al., Microwave
Journal , October 1995.
Presentation by Dr. Steven Brozovich at Fujitsu Compound Semiconductor, Inc. (408) 232-9570.
See the paper below. This routine matches the routine in the paper identically, which matches measured results
very well (within about 1dB).
______________________________________ Comparison to Measured Results
Peak_ave :=
ACPR 30_30spec 62dBC−:=
Best Casef off 100kHz:=
ACPR 30_30spec 47dBC−:=
Worst Casef off 50kHz:=
f ACPRBW 21kHz:=BW 21kHz:=
f 0max 956MHz:=f 0min 940MHz:=
Pout dBm=PoutPout 10 log1mW
⋅:=
PDC Hands et Specif ications
Peak_ave :=
ACPR 30_30spec 48dBC−:=
Best Casef off 60kHz:=
ACPR 30_30spec 30dBC−:=
Worst Casef off 30kHz:=
f ACPRBW 24kHz:=
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