spectrum analysis basics_rfd

8/4/2019 Spectrum Analysis Basics_RFD

http://slidepdf.com/reader/full/spectrum-analysis-basicsrfd 1/50

Signal Analysis

Back-to-Basics

Long Nguyen

[email protected]



Agenda

•Introduction

•Overview:

• What is Signal Analysis?

• What Measurements are available?

•Theory of Operation

•S ecifications

•Modern Signal Analyzer Designs & Capabilities

•

•Wrap-up

www.agilent.com/find/b2b

Slide 2



Overview,

•Display and measure amplitude versus frequency for RF & MW signals

Spectrum Analysis


Slide 3

•Separate or demodulate complex signals into their base components (sine waves)



Overview

Amplitude

ower

Time domain

Measurements

Frequency Domain

Measurements


Slide 4

(Oscilloscope) (Spectrum Analyzer)



Overview

T es of Measurements Available • Frequency, power, modulation, distortion & noise

• Spectrum monitoring

Modulation

• pur ous em ss ons

• Scalar network analysis• Noise figure & phase noise

•

• Analog, digital, burst & pulsed RF Modulation

• Wide bandwidth vector analysis• Electroma netic interference

Noise

• Measurement range (-168 dBm to +30 dBm)

• Frequency range (3 Hz to 325 GHz)

Spur Search


Slide 5

Distortion



Overview eren ypes o na yzers

Parallel filters measured

s mu aneous y

LCD shows full

A

spectra sp ay

f1 f2


Slide 6



Overview eren ypes o na yzers

Filter 'sweeps' over range ofSwept Analyzer

An eres

LCD shows full

f1 f2


Slide 7



Agenda

•Introduction

•Theory of Operation:

• Swept Spectrum Analyzer Hardware

•Specifications

•Modern spectrum analyzer designs & capabilities

• Wide Bandwidth Vector Measurements

•Wrap-up


Slide 8



Theory of Operation wep pec rum na yzer oc agram

npu

attenuatormixer

IF filter

(RBW) envelopedetector

IF gain

Pre-Selector

Or Low Pass

Input Filter

Log

Amp

video

signal

local

oscillator

sweep

Crystal

Reference

Oscillator

generator

ADC, Display


Slide 9

Processing



Theory of Operation

ReferenceLevel

l i t u d e

A m

Start Freq. Stop Freq.


Slide 10

Freq. Span Center Freq.



Theory of Operation MIXER

xer

fsig

fsig LO

f

LOf f

sig- LOf f

sig+RF

LO

IF

1.5 GHz

LOf3,6 GHz 6.5 GHz


Slide 11



Theory of Operation

IF Filter

(Resolution Bandwidth – RBW)

Input

IF Bandwidth

(RBW)

Display


Slide 12

A B C



Theory of Operation Before detector After detectornve ope e ec or

Envelope

Detector


Slide 13



Theory of Operation

Video

Filter

(Video Bandwidth – VBW)


Slide 14



Theory of OperationVideo Filter

Video Filter vs. Trace/Video averaging

ADC, Display &Video Processing

• Video Filter operates as the sweep

progresses, sweep time may be

required to slow down by the transientresponse of the VBW filter.

• Trace/Video Average takes multiple

swee s, swee time for each swee is

not affected

• Many signals give the same resultsTrace averaging for 1, 5, 20, and 100 sweeps, top to


Slide 15

w e er v eo er ng or race

averaging

o om race pos on o se or eac se o sweeps



Theory of Operation

SWEEP

GEN

LO

LCD Display, ADC

& Video processing

RF INPUT


Slide 16



Theory of Operation

-

Signal Range LO Rangefs

f - f(GHz)

0 3 61 2 4 5

0 31 2

mixer

IF filter

detector

f s

ssLO

3.6 GHz

f

input3.6 6.5

sweep generator

LO

A

(GHz)3 64 5

(GHz)0 31 2

LCD display

f

f LO


Slide 17

. .



Agenda

•Overview

•Specifications:

• Which are important and why?

•Modern spectrum analyzer designs & capabilities• Wide Bandwidth Vector Measurements

•Wrap-up


Slide 18



Key Specifications

8563ASPECTRUMANALYZER 9 kHz -26.5 GHz

• a e spec rum ana ys s

• Frequency Range

• Accuracy: Frequency & Amplitude•

• Sensitivity

• Distortion

• D namic Ran e


Slide 19



Specifications rac c ng sa e spec rum ana ys s - a e oo ups o npu

•

•Do not exceed the Damage Level on the RF Input!

•

!

+30dBm (1W) MAX


Slide 20



Specifications

requency angeDescription

Specifications

Bands

0 3 Hz to 3.0 GHz

2

3

. o . z

6.2 to 13.2 GHz

12.8 to 19.2 GHz

4

5

18.7 to 26.8 GHz

26.4 to 31.15 GHz

External mixing

. o . z18 to 325 GHz


Slide 21



Specifications

Components which contribute to uncertainty are:

•

• RF Input attenuator (Atten. switching uncertainty)

• Mixer and in ut filter fre uenc res onse

• IF gain/attenuation (reference level accuracy)

• RBW filters (RBW switching uncertainty)

• Log amp (display scale fidelity)

• Reference oscillator (frequency accuracy)


Slide 22

• Calibrator (amplitude accuracy)



Specifications ccuracy: requency ea ou ccuracy

Determined by

From the PSA Data Sheet:

± (freq readout x freq reference error +

0.25%*span + 5% of RBW + 2Hz + 0.5 x Horiz. Res.*)

RBW Error

Span Accuracy Residual Error


Slide 23

*Horizontal resolution is span/(sweep points – 1)



Specifications

Accuracy: Frequency Readout Accuracy Example

Frequency: 1 GHz

pan: z

RBW: 3 kHzSweep points: 1000

Calculation： (1x109Hz) x (±1.8x10–7/Year ref. Error) = 180Hz

400kHz Span x 0.25% = 1000Hz z x = z

2Hz + 0.5 x 400kHz/1000-1 = 202Hz

Total uncertainty = ±1532Hz

Utilizing internal frequency counter improves accuracy to ±180Hz

www.agilent.com/find/b2bSlide 24



Specifications

Resolution

RBW Type and


o se e an sSelectivity



Specifications

Resolution: Resolution Bandwidth

3 dB3 dB BW

Mixer

Envelope

Detector

InputSpectrum

LO

er

Resolution Bandwidth Filter (RBW)

Sweep

RBW

Display




Specifications

Resolution: Noise Sidebands

Phase Noise

Noise Sidebands can prevent


reso ut on o unequa s gna s



Specifications

Resolution: RBW Determines Sweep Time

Swept too fast

Penalty For Sweeping Too Fast


Is An Uncalibrated Display



SpecificationsResolution: RBW Type Determines Sweep Time

8563E Analog RBW

PSA Digital RBW

PSA FFT RBW

134 sec


13.5 sec



Specifications

Sensitivity/DANL

Mixer Detector

InputRES BW

Filter

LO

Sweep

A Spectrum Analyzer Generates and Amplifies Noise Just




Specifications

Sensitivity/DANL

Sensitivity is the Smallest Signal That Can BeMeasured

Signal2.2 dB

qua s

Noise




Specifications

Sensitivity/DANL

of RF Input Attenuation

10 dB

ttenuat on =

Signal To Noise Ratio Decreases as


nput ttenuat on s ncrease



Specifications

Sensitivity/DANL: IF Filter(RBW)

Displayed Noise is a Function of IF FilterBandwidth

100 kHz RBW

1 kHz RBW

10 dB


ecrease = ecrease o se



Specifications

Sensitivity/DANL: Video BW filter (or Trace Averaging)

Video BW or Trace Averaging Smoothes Noisefor Easier Identification of Low Level Si nals




Specifications

Sensitivity/DANL: Summary

Minimum RF Input Attenuation

Sufficient Averaging (video or trace)




Specifications

Distortion

and Third Order

< -50 dBc < -50 dBc< -40 dBc

Two-Tone Intermod Harmonic Distortion




IF GAINRF INPUT

ATTENUATOR

Specifications

Attenuator Test: Change power to the mixer

s or on – n erna or x erna

Change input attenuator

by 10 dB1

Watch distortion amplitude on

screen

2

distortion is part of input

signal (external)

Change in amplitude :at least some of the distortion is being

generated inside the analyzer


nterna



Specifications

pec rum na yzer ynam c ange

D namic

Range

The ratio, expressed in dB, of the largest to the smallestsignals simultaneously present at the input of the spectrum


given degree of uncertainty.



Agenda

•Introduction

•Overview


•Specifications

•

• Wide Analysis Bandwidth Measurements

• -




Modern Spectrum Analyzer Block Diagram

Analog IF

FilterDigital IF Filter Digital Detectors

Pre-amp

Di ital Lo AmSwept vs . FFTAttenuation

YIGADC

Replaced

by




Modern Spectrum Analyzer Block Diagram

Auto Alignment

AnalogPre-Filter

Digital IF Filters• 160 RBW filters

• 1 Hz to 8 MHz•±0.03 dB

switchin error

Digital Detectors•Normal

•Peak•Min

•Sam le

3 to 50 GHz Pre-amp

Improve 1 GHz

•RMS

•QPD

•Avg

• 4.1:1 Shape factor

• Fast sweep• EMI RBW’s

• emp t me ca rat on

FFT

DANL -153dBm

to -168dBm

Digital Log Amp

•±0.07 dB Scale Fidelity

• >100 dB Dynamic range

•

FFT vs Swept RBW• Faster Sweep

w/Max DR

Attenuation

2 dB step

to 50 GHz

g ta y ynt es ze

• Fast tuning• Close-in phase noise

• Far-out phase noise

• Wider dynamic rangewith autoranging

• Dither on/off

.

Frequency Counter

• Fast (0.1s)

• High resolution (mHz)

Digital Video Filters

• Power, voltage,

log filtering


M d S t A l F t



Modern Spectrum Analyzer Features

- -

GSM/EDGEPower MeasurementsFormat Setups

Occupied Bandwidth

Channel Power

cdma2000

W-CDMA

Multi-Offset ACP – fast ACP

Multi-carrier PowerNADC/PDC

Bluetooth

Harmonic Distortion

Burst Power

Tetra (Ch. Pwr, ACP)

802.11a/b (SEM)

TOI

Spurious Emissions

DVB-T

UWB


Spectral Emissions Mask S-DMB





Application Focused Internal Software (one-button measurements)

Phase noise

Ext. source controlGeneral purpose

ACPR, Multi-carrier Power

Occupied Bandwidth (OBW)

Noise figure

Code compatibility suite

Flexible demod

applications

Flexible digital

Phase and Freq. (PFER)

Mod Accuracy (Rho)

Spectral Emissions Mask

W-CDMA, HSDPA, HSUPA

GSM with EDGE

modulation analysisCode Domain Power

ORFS (GSM/EDGE)

Spurious Emissions

Cdma2000 & 1xEV-DV

1xEV-DO

ower g a

modulation

measurements for

wireless comms IM distortion

Power vs Time

Channel power

cdmaOne

NADC/PDC

formats.CCDF

ACPR

Flexible Digital Demod FormatsFSK2, FSK4, FSK8

MSK type1, MSK type2

BPSK, QPSK, OQPSK, DQPSK


TD-SCDMA

SEM

, ,

16QAM, 32QAM, 64QAM

128QAM, 256QAM

Who needs wide analysis BW?



Modern designs demand more bandwidth for capturing high data rate

Who needs wide analysis BW?

• Aerospace and Defense

–

s gna s an ana yz ng e qua y o g a y mo u a e an w s

Satellite – Capture 36/72 MHz BW’s w/high data

ratesMilitary communications – Capture high data rate

digital comms & measure EVM

• Emerging communications

W-LAN, 802.16 (wireless last mile), mesh networks

- Measure EVM on broadband, high data rate signals

• Cellular Communications

W-CDMA ACPR & Multi-carrier Pre-Distortion

- High dynamic range over 60 MHz BW to see low


-

algorithms

PSA Wid A l i B d idth



PSA Wide Analysis Bandwidth

Swept

Results

14 bit

30 MspsPre-filter

CPUExisting

Narrowband

I/QDetectorsLog Amp

RBW filters

Autorange

DisplayProc

Demod

FFT Display

(10 MHz)

Decimation

ASIC&

FPGA

I/Q Detectors14 bit

200 Msps

Swept

andWideband

IF/DigitizerDemod

DecimationResampling

tepped

LO (80 MHz)MemoryCalibration





80 MHz Analysis Bandwidth Snapshot


w/Real Time, Calibrated, Digital IQ Detection




Agenda

•Introduction

•Overview


•Specifications

•

• Wide Analysis Bandwidth Measurements

• -


Agilent X Series Signal Analysis



Agilent X-Series Signal Analysis

that spans instrumentation, measurements and software

PSA

Market leading

PXA

X-Series

Sep 09

P r i c e MXA

X-Series

performance3 Hz to 50 GHz

Sep 06

High performance3 Hz to 26.5 GHz

EXA

Mid performance

20 Hz to 26.5 GHz

Expanded backward code

compatibility with 8566/68

on PXA /MXA/EXA

Sep 07

-

Economy class9 kHz to 26,5 GHz

ESA

World’s most popular100 Hz to 26.5 GHz

Se 09

CXA

X-Series

Low cost

89601B VSA software

See through the complexity!

9 kHz to 7.5 GHz PerformanceHSA

Basic-performance

9 kHz to 3 GHz

Applications Available on the PXA



pp

(frequency band up to 50GHz w/ FW Rev. A.08.03)

ew pp ca ons n ev. . .

Web-downloadable in June, 2011

N6158A CMMB N6153A DVB-N9062AN9063A

N9071A GSM/EDGE/

N9080/N9082A LTE

o e

WiMAX

N6152A Digitalcable TV

T/H with T2

N6155A ISDB/T

FSP/FSU/FSE

compatibility

Analog demod

N9068A

N6171A

MATLAB

N9061A

New

vo

N9073A W-

CDMA/HSPA/+

N9072A cdma2000/

New

N9081A Bluetooth

N6156A DTMB

w mmase no se

N9069A

Noise Figure

865xE/EC & 8566/68

compatibility

N9051A*

N9079A

TD-SCDMA/ N9076A

New

Enhanced

N9064A

VXA

Pulse

HSPA/8PSK 1XEV-DO

N6149A

iDEN/WiDEN/

EMC MotoTalk

* The pulse measurement applications be upgradable in September 2011

The Agilent HSA family



The Agilent HSA family

N9340B 3GHz HSA N9342C 7GHz HSAN9344C 20GHz HSA

Apr 2008 Aug 2010 Mar 2011

Higher frequency

Better performance

N9343C 13.6GHz HSAInnovative features

features

Award winning product

100 kHz to 7 GHz (tunable to 9

kHz)

1 MHz to 20/13.6 GHz (tunable to

9 kHz)es - n-c ass spec ca ons

Unique applications:

AM/FM IBOC and xDSL

Innovative task planner

Built-in GPS receiver and

antenna

New features include

AM/FM modulation analysis

Time-gated spectrum analysis Secure erase of user data

5-year contract won

from US Navy Agilent 1st μwave

11-language support

Agilent 1st μwave

analyzer

analyzerComply with MIL-PRF-28800F Class 2

spectrum analysis basics_rfd

Documents