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

1



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←:=

2



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=

3



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 ,( )−:=

4



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=


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


BW 19.2kHz 64⋅:= BW 1.229MHz=f ACPRBW 30kHz:=


5



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 :=


Best Casef off 100kHz:=


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 :=


Best Casef off 60kHz:=


Worst Casef off 30kHz:=

f ACPRBW 24kHz:=

6

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