DPD/ETPA/RFIC, Multi - port device test for

Intelligent device

1

Keven Chang 張啟文 Module Specialist

Agenda

1. Key Intelligent Device Challenges

2. Technology Overview

3. Measurement Considerations

4. Measurement Architectures & Solutions

5. Q&A

2

Challenges – Lower Heat

08-May-12

Modular Solutions Presentation

3

Challenges – Longer Battery Life

USD$15~ $60.

2,000~ 20,000 mA/h. 2,000~ 4,000 mA/h.

Challenges – Lower Size ? & Testing Cost

08-May-12

Modular Solutions Presentation

4

Ever look under the hood of a Smartphone?

Agenda

1. Key Intelligent Device Challenges

2. Technology Overview

3. Measurement Considerations

4. Measurement Architectures & Solutions

5. Q&A

6

Digital Pre-Distortion (DPD) Why & How

Modern communication systems

• Signals have high peak-to-average power ratios (PAPR).

• Must operate with high power-added efficiency (PAE).

High PAPR is a consequence of high spectral efficiency

• Multiple-Carrier Signals (MC GSM, MC WCDMA)

• CDMA (WCDMA, CDMA2000)

• OFDM (LTE, WiMAX)

High PAE is achieved when the RF power amplifier (PA) is driven towards saturation

Operation near saturation inherently results in higher signal distortion

Maximum

correctable

power

Psat

INPUT

POWER

OUTPUT

POWER

LINEAR

REGION

DPD

REGION

LINEARIZED

DPD + PA

PA, WITH GAIN

COMPRESSION

DPD GAIN

EXPANSION

+ =

7

DPD corrects PA nonlinearities resulting in higher performing power amplifiers

DPD Architecture and Bandwidth Requirement

Digital

Pre-

Distortion

RF

Up-converter Coupler PA

DPD

Extraction

and Control

RF Down-

Converter &

Digitizer

3-5 x BW 3-5 x BW 3-5 x BW

3-5 x BW 3-5 x BW

Sample rate must be 3-5 x the BW of the RF signal

7/3/2014

Techniques to Reduce Characterization Test

Times of PAD Devices 8

Before DPD After DPD

Poor EVM Good EVM

Poor ACP Good ACP

Volterra Series Adaptive Process

Memory Polynomial Process

LUT Adaptive process

Dynamic EVM The Why & How

A Simplified Envelope Tracking Technique

Used for Wireless LAN

• Device is turned off between packets

to conserve power

• Testing must ensure device turns on & off

quickly without negative transient or

thermal effects

Dynamic EVM test method

• Square wave pulse applied to PA enable

(during RF burst)

Test equipment same as

for envelope tracking

9

Wireless LAN Brust Signal

PA ON/OFF Signal Time advance (Before & After)

• Improve battery life

• Increase RF amplifier performance over broad frequencies

• Lower distortion

• Reduce heat dissipation

Envelope Tracking - The Why & How

The RF Signal Envelope & Carrier

1 LTE symbol 10us/

1 LTE frame 1ms/

The envelope 0.1-1us/

The RF carrier 1-2ns/

A

The Evolution of a Handset PA

Techniques to Reduce Characterization Test

Times of PAD Devices 12

Generalization of PAD

(Power Amplifier Duplexer) architecture

Techniques to Reduce Characterization Test

Times of PAD Devices 13

Filters &

Duplexer

Antenna

Switch

RF

Transceiver

PA

DC Supply

DC Modulator

MIPI

RFFE

Device Control

Filters &

Duplexer

Filters &

Duplexer

PA

Rx

Rx

Rx

IQ Envelope

Mode

Switch

Agenda

1. Key Intelligent Device Challenges

2. Technology Overview

3. Measurement Considerations

4. Measurement Architectures & Solutions

5. Q&A

14

Review – ACPR Adjacent Channel Power (Leackage) Ratio (ACLR)

08-May-12

Modular Solutions Presentation

15

Review - AM/AM Measurement

with Swept CW Stimulus

Low Power

Middle Power

High Power

ACPR

Review - AM/PM Mechanism

Power Source Cannot Supply Current

“Clipping” Amplitude Changes Average Offset

New “Zero Crossing” Offset Creates AM/PM

Q

VInput

VGS

IDS

IOutput

Df

Df Df

Review - PAE (Power Added Efficiency)

PA

E

RF output voltage

PAE ~ RF Pout

Supply Pin

100%

50-60%

at peak

output

What you want

What we expected!

Power

Added

Efficiency

ET Tech. Inside

08-May-12

Modular Solutions Presentation

19

08-May-12

Modular Solutions Presentation

20

ET Tech. Inside

ETPS Envelop Detector Shaping Table (LUT)

Vcc

RFout RFin

Vin

Need to oversample the IQ

waveform because envelope

bandwidth is wider than RF

(squaring effect)

The shaping table is derived

from the PA characteristics

and system design goals /

trade-offs

The shaping table and time

alignment depend on RF path

settings and RF frequency

PA

Supply

voltage

RF output voltage

• Supply does not go to 0V

• PA operating in linear range

• PA input determines output

performance

• Smooth transition controls

envelope bandwidth

• Voltage may not be limited

• Higher peak voltage extends

PA operating range

• PA in compression

• Supply determines PA output

amplitude

• Curve sets PA amplitude

linearity and efficiency

• Supply does not go to 0V

• PA operating in linear range

• PA input signal largely

determines output distortion

• Voltage not always clipped

• Clipping gives simple CFR

• Higher peak voltage extends

PA operating range

Envelope Shaping (de-Troughing) Design

• PA in compression

• Supply determines PA output

amplitude

• Curve sets PA amplitude

linearity and efficiency

A

RF spectrum The main power

content has the same

bandwidth as the RF log m

agnitude

RF center

frequency DC

Constant scaling

(MHz / div)

Distortion

(ACP)

DC

component

The Envelope Spectrum & How to Control It

The roll off

depends on use of

shaping curve to

minimize sharp

signal transitions

Envelope

spectrum

The roll off

depends on use of

shaping curve to

minimize sharp

signal transitions

ET PA takes

less power

+23 dBm PA output

Yes - Reduction in Average Power

ET PA, ETPS & System Analysis

Linearity & time alignment Mixed RF & Baseband

24

Does ET work? Fixed supply

Does ET work? Tracking supply

PA operating in ET

mode has less

distortion

PA operating in ET

mode has less

distortion

PA operating in ET

mode has less

distortion

PA operating in ET

mode has less

distortion

A

08-May-12

Modular Solutions Presentation

27

Timing Misalignment

Timing Misalignment Causes ACP Variation

28

5 MHz LTE 25RB 1ns steps

A

Generalization of PAD

(Power Amplifier Duplexer) architecture

Techniques to Reduce Characterization Test

Times of PAD Devices 29

Filters &

Duplexer

Antenna

Switch

RF

Transceiver

PA

DC Supply

DC Modulator

MIPI

RFFE

Device Control

Filters &

Duplexer

Filters &

Duplexer

PA

Rx

Rx

Rx

IQ Envelope

Mode

Switch

Generalization of PAD

(Power Amplifier Duplexer) architecture

08-May-12

Modular Solutions Presentation

31

Generalization of PAD

(Power Amplifier Duplexer) architecture

Filter / Duplex Filtering Testing

An FDD radio has to isolate the transmit & receive paths

This is typically implemented using a pair of SAW or

FBAR band pass filters

A VNA measurement shows how reflections from a filter

with adequate rejection may have significant group delay

ripple in S11

-100.00

-50.00

0.00

50.00

100.00

150.00

200.00

0

0.2

0.4

0.6

0.8

1

1.2

8.70E+08 8.90E+08 9.10E+08 9.30E+08 9.50E+08 9.70E+08

S11 group

delay

S21 pass-band

S11 return loss

Techniques to Reduce Characterization Test

Times of PAD Devices 32

Agenda

1. Key PA Challenges & Technology

2. ET Measurement Considerations

3. Measurement Architectures & Solutions

4. Q&A

33

Power Amplifier Test Solutions

34

• PA Testing Solutions Across Product Delivery

Design Verification Production

LXI

Benchtop

PXI

Modular

ETPA (Envelop Tracking Power Amplify)

Benchtop Solutions for R&D and DVT

35

RF Out RF In

Vcc Vbat

RFFE

PA

ETPS

ET Waveform

I/Q Waveform

AWG: 33522B

Proprietary

Control

Trigger V.. V..

SystemVue , Simulation s/w

Generated Waveforms

Signal Generation

s/w

or

DC Power Analyzer

N7605B

VSA

VSG : M5182A

DSO9000

VSA s/w

High performance,

low cost envelope

generation

Time alignment & linearity

(AM/AM, AM/PM, Gain

compression)

Waveform creation

includes shaped envelope

& envelope download

Soltuions

AM/AM

AM/PM

Gain Compression

PAE

ACLR

Delta EVM

Dynamic EVM

Shaping Table

Example:

Scout RFFE

USB Dongle

PAD Production Test Solution

Typical Configuration

36

RF Out RF In

Vcc Vbat

V.. RFFE V..

PA

ET Waveform

I/Q Waveform

M9381A

VSG

6 GHz

M9391A

VSA

AWG

SingalDyne

Trigger

ETPS

USB Power Meter(s)

Waveform

Generation

s/w

Harmonics

testing

Embedded

Controller

M9037A

18 slot PXI chassis

Note: RF switching modules omitted for clarity

PA S-parameters

DUT control

(Optional)

Microwave

M9393A

VSA

M9375A

VNA

M9195A

DIO/PPMU

SMU

AM/AM

AM/PM

Gain Compression

PAE

ACLR

Delta EVM

Dynamic EVM

Shaping Table

20/6V, 1/3A 20W 4Q SMU

20/6V, 1/3A 20W 2Q SMU

U2021XA USB RF sensors

Duplexer

Ready to Go Measure

M9391/M9393A VSA , FPGA Engine

Ready to Go for Speed Implement

FPGA

PCIe

FFT Measurement

Power Measurement

Adjacent Channel Power

Measurement

Process & Calc.

• FFT

• Power

• EVM ….etc Key Features:

• Extremely fast Power Measurements

• Baseband tuning for fast ACPR Measurements

• Real-time corrections

• PXIe (PCIe) data bus for fast data transfer and test execution

• Soft front panel, IVI-COM drivers,

and connectivity to 89600 VSA software,X’App & SystemVue

• Controller Base Software License Benfity

• FPGA Engine (Ready to Go)

• Sweep Speed (Inetel I7 : ~ 85GHz./s)

M9381A VSG

38

RF/MW

DAC

DAC

LPF

Q

90 LO

I

I/Q

Waveform

File

16 Q RAM

16

16

16 I RAM

I/Q modulator (Up Converter)

LPF

ALC 16

16

Baseband Generator

160

MS/s

Q

90 LO

I

Baseband Frequency and Amplitude Offset

with the M9381A Vector Signal Generator

160

MHz

20 dB

< 200 us

• Signal Processing ASIC in baseband generator supports changing Frequency and Amplitude of RF Signal

without Adjusting Analog Hardware (fastune technology innovation)

• Power Servo Loop Approach:

• Set the “RF Power Level” to the maximum level that may be required from the source

• Use the “baseband power level” to adjust the power level to the required input level

• <200 us amplitude changes using command interface ,<10us (List Mode)

M937x Multiport VNA

Measurements for PA , Duplexer , Switch

Multiple M937xA VNAs in PXI

For best performance, you need:

• True multiport VNA with independent modules

• Improved throughput

• High fidelity measurements without needing

external port switches

• Full N-port correction

Techniques to Reduce Characterization Test

Times of PAD Devices 39

Filters &

Duplexer

Antenna

Switch

RF

Transceiver

PA

DC Supply

DC Modulator

MIPI

RFFE

Device Control

Filters &

Duplexer

Filters &

Duplexer

PA

Rx

Rx

Rx

IQ Envelope

Mode

Switch

M937x PXI VNA

40

Options

010 : Time domain

551 : N-port calibrated measurement

102 : Additional VNA features and capabilities

Fixture simulator Manual & automated port extend & Equation editor

897 : Built-in performance test software for inclusive calibration

898 : Built-in performance test software for standards compliant calibration

32-port True Crossbar 26.5 GHz VNA in 4U Chassis

M937X PXI VNA Performance

41

8

16

24

Nu

mb

er

of p

ort

s o

n D

UT

Number of sweeps for an N-port measurement

100 200 300 400 500 0

56

8

240

112

16

552

264

24

24

M937xA with 24-ports

4-port Switch Matrix VNA

2-port Switch Matrix VNA

Cycle Time

M9372A

8753ES 848 msec

57 msec

1,601 pts, full 2-p cal, small span

IFBW = 6 kHz (8753ES), 500 kHz (E5071C) 600 kHz (M9372A)

x15 faster

E5071C 41 msec

Trace Noise Dynamic Range

IFBW = 10 Hz,

Max specified power

The same quality results you have

come to expect in our VNA

Keysight Phase 2 (2014.Sept. 15th)

Reference Solution Block Diagram

Drivers

Device Under Test Hardware Software Application

Target Market - RF PA production test

- RF PA DVT with ET/DPD test

Description - High Speed ET, DPD

- > 6 GHz Harmonics

- Multi-port VNA

New features - Agilent modules : VNA, M9393A VSA

- 3rd party modules : AWG

- Software : Signal Studio for RF PA

PXI VSG

ETPS

Reference

Solution Libraries

X-Apps

Signal

Studio for RF PA

+ LTE

Reference

Solution

GUI

PXI VSA

Customer

Test

Applicatio

n

RF PA

RFFE

PXI VNA

LXI SMU

USB DIO

Duplexer

eFTD Sept 2014

PXI AWG Signadyne

08-May-12

Modular Solutions Presentation

43

M9451A FPGA DPD PXIe Measurement Accelerator

08-May-12

Modular Solutions Presentation

44

M9451A DPD FPGA speeds up DPD/ET test applications Key features include:

Digital Pre-Distortion

– Open or closed loop

– PA optimization techniques: Look up table (LUT)

– Fast peer-to-peer (P2P) data transfer to/from PXI signal generator and signal

analyzer

Envelope Tracking

– Hardware accelerated envelope tracking waveform generation

– Fast data transfer to arbitrary waveform generator (AWG

M9451A Digital Pre-Distortion and Envelope Tracking Block Diagram

PA Test Reference Solution Phase 3 - Resource Manager, X’App , SFP IVI Measure

- Application WCDMA,CDMA2K,EVDO,TD-SCDMA,LTE,WLAN

- Testing Item

- Power Servo

- DC Current

- ACPR

- EVM

- Harmonic

- SEM

- ETPA

- DPD

- DC: SMU

- ET : ARB

- RFFE

- Power Sensor

- Calibration

-Speed Performance.

08-May-12

Modular Solutions Presentation

46

M9381A VSG Key Features:

• Frequency range: 1 MHz to 3 or 6 GHz (options)

• Modulation bandwidth: 40, 100, 160 MHz (options)

• Phase Noise (10 kHz offset @ 1GHz carrier) -125 dBc/Hz typical

• Frequency Settling Time to within 1kHz <220 us

• <10 us utilizing baseband tuning within modulation BW (+/-80 MHz)

• Amplitude Settling Time <120 us

• <10 us for changes 0 to 20 dB utilizing baseband tuning within modulation BW (+/-80 MHz)

• RF Flatness Corrected <0.4 dB (140 MHz BW)

• Min/Max Output power -120dBm (Specified, settable to -130 dBm) /+19dBm

• Real-time corrections

• Generator Memory 1024 MSa

• PXIe (PCIe) data bus for fast data transfer and test execution

M9393A VSA Key Features

• 9KHz~8.4/14/18/27 GHz (upgradeable Solftware Options)

• 40/100/160 MHz Bandwidth (upgradeable Solftware Options)

• ~ 150 us Frequency Tuning

• ~ 10 us Amplitude Switching

• +/- 0.15 dB Amplitude Accuracy across frequency and temperature

• Connectivity to 89600 VSA, Modular X-Apps, Modular spectrum application

• Power Spectral Engine for fast spectrum capture (FFT-based)

• 27GHz. Sweep ~ 1 Second (RBW: 10KHz)

M9391A VSA Key Features:

• Frequency range: 1 MHz to 3 or 6 GHz (options)

• Analysis bandwidth: 40, 100, 160 MHz (options)

• Absolute amplitude accuracy ±0.7 dB to 3 GHz, and ±0.9 dB to 6 GHz

• TOI +23 dBm

• Displayed average noise level -140dBm/Hz (-156dBm/Hz with PreAmp)

• WCDMA ACLR Dynamic Range -68 dBc

• Real-time Power Measurements

• Baseband tuning for Fast ACPR Measurements

• Real-time corrections

• PXIe (PCIe) data bus for fast data transfer and test execution

PXI Hardware Reference

08-May-12

Modular Solutions Presentation

47

M9195A DSR Key Features & Specifications

16 per pin programmable channels for logic levels, delay

Parametric Measurement Unit (PMU) per channel

Single and multi-site configurability

Flexible per bit timing control

On-the-fly pattern generation and editing

Allocation of deep pattern memory per channel

High voltage drivers and open drain control pins

Software tools for quick test development

M937xA PXI VNA Key Features & Specifications

Full 2-port S-parameters in a single-slot module

N-port multiport configurations available with multiple modules

Configurable as multiple independent VNAs

Compatible with electronic calibration (ECal) modules

Test multiple devices simultaneously, with multi-VNA capability

Test multiport devices faster than using switch matrices

The fastest measurement speed in a PXI VNA

Best accuracy derived from the best PXI VNA specifications

Fast sweep speed: 18 msec, 401 points, 600 kHz IFBW

Dynamic range: 95 dB specified at 24 GHz, 65 dB typical at 26.5 GHz

Trace noise: 0.006 dB at 24 GHz, 0.020 dB at 26.5 GHz

Stability: ± 0.020 dB/ºC

PXI Hardware Reference

M9451A DPD FPGA speeds up DPD/ET test applications Key features include:

Digital Pre-Distortion

– Open or closed loop

– PA optimization techniques: Look up table (LUT)

– Fast peer-to-peer (P2P) data transfer to/from PXI signal generator and signal

analyzer

Envelope Tracking

– Hardware accelerated envelope tracking waveform generation

– Fast data transfer to arbitrary waveform generator (AWG

08-May-12

Modular Solutions Presentation

48

M9210A Digitize Scope Key Features & Specifications

Up to 4 GS/s sampling rate and 1.4 GHz bandwidth

Large on-board memory up to 256 MSa/channel

Selectable 50Ω/1MΩ input impedance

Performance characteristics

PXI-H 1-slot 3U, 100 MB/s data transfer

1.4 GHz BW in 50Ω and 300 MHz BW in 1MΩ

15 ps accuracy Trigger-Time-Interpolator

SD AOU-H3353 500 MS/s, 16 Bits, 2 Ch, AWG Key Features 2 output channels

500 MSPS per channel, 16 bits

DC to 200 MHz output frequency

Advanced Arbitrary Waveform Generators

Advanced queue system and triggering

High-precision Function Generators

Sinusoidal, triangular, square, etc.

Ultra-flexible angle / amplitude modulators

Any modulation: AM, FM, PM, ASK, FSK, PSK, etc.

Simultaneous amplitude and angle modulation

High-quality output signal with low phase noise

16 MB, 128 MB or 1 GB of RAM

HW programming using Signadyne HVI real-time technology

Up to 1.6 GB/s transfer speed with P2P capabilities (PCIe Gen 2)

1 slot 3U

PXI Hardware Reference

Summary

49

ET is fast becoming an important capability for PA’s supporting linear modulation schemes

ET provides: Improved PA efficiency Lower distortion Broader frequency coverage Longer handset battery life

ET measurements and characterization can be challenging Agilent Technologies can provide the needed hardware and

software needed for ET systems testing from R&D through DVT to Production test

Reference Material

50

www.agilent.com/find/envelope_tracking

• Envelope tracking solution guide

• Videos: ET signal generation and analysis

• App Note: Simulating ET in ADS

• Article: X-parameter models for an RF PA using ET

EEsof RF Power Amplifier Design Webcast Series

• Part 5: Envelope Tracking Simulation and Analysis

Questions

51

Additional Reading:

OpenET Alliance

Simulation and X-parameter Models for PA’s with ET

Envelope Tracking Simulation and Analysis