Technology Trend in Spectrum Analyzer

Technology Trend in

Spectrum Analyzer

Roberto Sacchi

Agenda

– The Wireless communication market

– Swept vs. FFT spectrum analyzer (resolution, selectivity)

– Digital modulation basics

Wireless Communications Market

A-GPS

W-CDMA

GSM

1xEV-DO

cdma 2000

EGPRS

S-DMB

FM Radio

802.11

“WiFi”

Bluetooth

MediaFLO

DAB

UWB

WiMAX

™

iR

DVB-H

HSDPA

WiBro

TDMB

HSUPA

RFID

Over the next few years we will see an

increasing number of devices

that include a combination

of wireless access technologies

Extraordinary Growth for Wireless Data

as Cellular and Wireless

Connectivity Merge

R&D

Validation

Manufacturing

Deployment

Continual Evolution of

Technologies

The trend in the wireless industry

Analog Modulations

AM/FM/PM

Time-variant

Vector Modulations

TDMA

GSM

Blue too th

Vector Modulations

PSK/QAM/FSK

MW Radio Links

“Coded”

Vector Modulations

CDMA/OFDM

3GPP WCDMA

WLAN

WiMAX

DVB-T/H

LTE

Overview

What is Signal, Vector and Spectrum Analysis?

•

_{Display and measure amplitude versus frequency for RF & MW signals}

•

_{Separate or demodulate complex signals into their base components}

_{(sine waves)}

Overview

Types of Tests Made

Modulation

Noise

Theory of Operation

Swept Spectrum Analyzer Block Diagram

Pre -Se le cto r

Or Lo w Pass

Input Filte r

Crystal

Re fe re nce

Oscillator

Log

Am p

RF input

atte nuato r

m ixe r

IF filte r

(RBW)

e nve lo pe

de te cto r

vide o

filte r

lo cal

o scillato r

swe e p

ge ne rato r

IF gain

Input

signal

ADC, Display &

Vide o

Pro ce ssing

Modern Spectrum Analyzer Block Diagram

YIG

ADC

Analog IF

Filter

Digital IF Filter

Digital Log Amp

Digital Detectors

FFT

Sweep vs . FFT

Attenuation

Overview

Different Types of Analyzers

Paralle l filte rs m e asure d

sim ultane ously

A

f

f

1

f

2

FFT Analyzer

A

f

f

1

f

2

Filte r 'swe e ps' ove r

range of inte re st

Modern Spectrum analyzer

Resolution: Resolution BW

3 dB

1 0 kHz

10 kHz RBW

Modern spectrum analyzer

Resolution BW Selectivity or Shape Factor

3 dB

60 dB

60 dB

BW

60 dB BW

3 dB BW

3 dB BW

Se le ctivity =

Specifications

Resolution: RBW Type and Selectivity

DIGITAL FILTER

ANALOG FILTER

Typical Se le ctivity

Analog 1 5:1

Digital

≤

_5:1

(Analog or Digital)

Modify a Signal

"Modulate"

Detect the Modifications

"Demodulate"

Any

reliably detectable

change in signal

characteristics can carry information

(As a Function of Time)

Amplitude

Frequency

Phase

Both Amplitude

and Phase

The rectangular coder

01

₀₀

1 0

1 1

...0 1 0 0 1 1 0 0...

Q

I

Mapping bits onto analog wave form s

I

Q

Creating Digital Modulation

We have used the concept of Signal

Space to view our modulations.

We can use the same idea to

engineer these modulations.

90º

Σ

I

Q

I

Q

(1,1)

(0,0)

(0,1)

(1,0)

+1volt

−

1volt

+1volt

−

1volt

(0,1)

+1v

−

1v

f

_C

FFT Analyzer Block Diagram

Anti-alaising and

Sampling

ADC

F

ADC Assembly

(time)

Re-Sampling

90

phase

shift

Digital Filter assembly

Real Part (I)

Imaginary Part

D

e

m

o

d

W

i

n

d

o

w

F

F

T

D

I

S

P

L

A

Y

DSP

(freq)

(demod time)

φ

Digital Data Flow

(Q) Quadrature

Measurements on digital radios

Time Domain

(CCDF, pulse shaping, tim ing)

_{Frequency Domain}

(Channe l Powe r, spe ctrum m ask,…)

Modulation Domain

• Ove rall Modulation Quality,

• Modulation Quality on individual carrie rs

• Channel Response , Group De lay

• In Channe l Spurious Se arch

Swept Spectrum Analyzer

(with span zero and enough ResBW)

Measurements in the frequency domain:

- Channel power

and occupied bandwidth

Modulation Quality Analysis

Modulation Error

Basic Concept:

Ideal point

Measured point

Measured Signal

at decision time

Ideal Signal

at decision time

I

Q

Error Vector

Measured signal is never equal to ideal signal, due to noise, transmitter

impairments, propagation phenomena,…

EVM[%]

MER[dB]

I/Q Impairments:

I/Q gain imbalance, Quadrature errors, I/Q offsets

Significant m e asure m e nts: conste llation and EVM m e trics

I/Q im pairm e nts are typically cause by m atching proble m s due to

EXA

X-Series

Economy class

9KHz to 26 GHz

CSA

Low cost portable

100 kHz to 6 GHz

Agilent Spectrum Analysis Portfolio

N9320B

Basic

performance,

Benchtop

Performance

ESA

World’s Most Popular

100 Hz to 26 GHz

Price

N9340B

Hand Held

MXA

X-Series

Mid Performance

20 Hz to 26 GHz

PSA

Market Leading

Performance

3 Hz to 50 GHz

89600 VSA Software

World’s best analysis & troubleshooting

8560EC

Series

Super mid-

performance

Ne w backwards CC

with 856x

o ptio n o n X-Se rie s

Cod

e Co

mpa

tible

Se p 06

Se p 07

Apr 08

Jul 08

Spec

EXA Signal Analyzer

MXA Signal Analyzer

PSA Analyzer

Frequency Range

9kHz

to 3.6/7/13.6/26.5 GHz

20 Hz

to 3.6/8.4/13.6/26.5 GHz

3 Hz

to 6.7/13.2/26.5

or 42.98/44/50 GHz

TOI

+13 dBm

_{+9 dBm}

+15 dBm

_{+10 dBm}

+17 dBm

_{+12 dBm}

DANL

-146 dBm/Hz

_{-137 dBm/Hz}

-151 dBm/Hz

_{-142 dBm/Hz}

-153 dBm/Hz

_{-147 dBm/Hz}

Φ Noise

-99 dBc/Hz

-130 dBc/Hz

-103 dBc/Hz

-133 dBc/Hz

-116 dBc/Hz

-145 dBc/Hz

W-CDMA ACPR

With noise correction

-68 dBc

-73 dBc

-73 dBc

-78 dBc

-74.5 dBc

-81 dBc

Amplitude Accuracy

±0.95 dB

0.27 dB

±0.78 dB

0.23 dB

±0.62 dB

0.19 dB

Analysis BW

10 MHz

10, 25

MHz

10,

40, 80MHz

Relative Speed

Fastest

Fastest

Faster

Base Price

_{$16.9k - $35.9k USD}

_{$27.9k - $45.9k USD}

_{$50k - $58k USD}

Summary

Digital platform key points



Greater selectivity and resolution with digital filter



Speed and dynamic range trade off (FFT vs Swept)