01 Basic Spectrum Analysis 1_rev

7/28/2019 01 Basic Spectrum Analysis 1_rev

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Basic Spectrum

Analysis

By

CSG Solution(Thailand) Ltd.

www.csgs.co.th


2/34

Table of Contents

Overview Theory of Operation Specification Measurements


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1sa Teerapong Sae-Jew ppt

1For internal use only

Basic Spectrum Analysis

2sa Teerapong Sae-Jew ppt

2For internal use only

8563ASPECTRUM ANALYZER 9kHz -26.5GHz

Basic Spectrum Analysis


4/342

33sa

Agenda

Overview

Theory of Operation

Specifications

Measurements

44sa

Overview

What is Spectrum Analysis?



5/343

55sa

Overview

Types of Tests Made

Modulation

Distortion

Noise

66sa

Overview

Frequency versus Time Domain

Amplitude

(power)

Time domain

MeasurementsFrequency Domain

Measurements


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77sa

Overview

Different Types of Analyzers

Parallel filters measured simultaneously

CRT shows full spectral

display

A

ff1

f2

Fourier Analyzer

88sa

Overview

Different Types of Analyzers

A

ff1 f2

Filter 'sweeps' over range of

interest

CRT shows full spectral

display

Swept Analyzer


7/345

99sa

Lab : Tune ,Zoom and Measure

Chanllenge

Find a signal

Resolve its sidebands

Measure the receiver

frequency and amplitude

What you learned

Its easy

1010sa

Lab : Tune ,Zoom and Measure

Contd

Step 1: Preset

Step 2: Tune

Step 3: Zoom

Step 4: Adjust Reference Level

Step 5: Measure


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1111sa

Agenda

Overview

Theory of Operation

Specifications

Measurements

1212sa

Theory of Operation

Spectrum Analyzer Block Diagram

Pre-Selector

Or Low Pass

Filter

Crystal

Reference

Log

Amp

RF input

attenuator

mixer

IF filterdetector

video

filterlocal

oscillator

sweep

generator

IF gain

Input

signal

CRT display


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1313sa

Theory of Operation

Mixer

MIXER

fsig

LOf

fsig LO

f

LOf

fsig

-LOf

fsig

+

RFLO

IF

input

1414sa

Theory of Operation

IF Filter IF FILTER

Display

InputSpectrumIF Bandwidth(RBW)


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1515sa

Theory of Operation

Detector

DETECTOR

Negative detection: smallest value

in bin displayed

Positive detection: largest value

in bin displayed

Sample detection: last value in bin displayed

"bins"

amplitude

1616sa

Theory of Operation

Video Filter

VIDEOFILTER


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1717sa

Theory of Operation

Other Components

CRT DISPLAY

SWEEP GENLO

IF GAIN

frequency

RF INPUTATTENUATOR

1818sa

Theory of Operation

How it all works together

3.6

(GHz)

(GHz)

0 3 61 2 4 5

0 31 2

3 64 5

3.6

(GHz)0 31 2

fIF

Signal Range LO Range

fs

sweep generator

LO

CRT display

input

mixer

IF filter

detector

A

f

fLO

fs

fs

fs

fLO

-fs

fLO

+fLO

3.6 6.5

6.5


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1919sa

Agenda

Overview

Theory of Operation

Specifications

Measurements

2020sa

Specifications


Frequency Range

Accuracy, Frequency & Amplitude

Resolution

Sensitivity

Distortion

Dynamic Range


13/3411

2121sa

Specifications

Frequency Range

Measuring harmonics

50 GHz and beyond!

Low frequencies

for baseband and IF

2222sa

Specifications

Accuracy

Absolute

Amplitudein dBm

Relative

Amplitudein dB

Relative

Frequency

Frequency


14/3412

2323sa

Specifications

Resolution: Resolution Bandwidth

3 dBdBBW

LO

Mixer

IF Filter/Resolution BandwidthFilter (RBW)Sweep

Detector

InputSpectrum

Display

RBW

2424sa

Specifications

Resolution: Resolution Bandwidth

3 dB

10 kHz

10 kHz RBW


15/3413

2525sa

Specifications

Resolution: RBW Type and Selectivity

3 dB

60 dB

60 dBBW

60 dB BW

3 dB BW

3 dB BW

Selectivity =

2626sa

Specifications

Resolution: RBW Type and Selectivity

10 kHz

RBW = 10 kHzRBW = 1 kHz

Selectivity 15:1

10 kHz

distortion

products

60 dB BW =

15 kHz

7.5 kHz

3 dB

60 dB


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2727sa

Lab : Resolving equal and unequal

amplitude signals

Chanllenge

Resolve two equal

amplitude signals

Resolve two unequal

amplitude signals

Measure absolutes and

differences What you learned

Resolution Bandwidth

Markers , marker function

2828sa

Specifications

Resolution

Resolution

Bandwidth

Residual

FM

Noise

Sidebands

What Determines Resolution?

RBW Type and

Selectivity


17/3415

2929sa

Specifications

Resolution: Residual FM

Residual FMSmears the signal

3030sa

Specifications

Resolution: Noise Sidebands

Noise Sidebands can preventResolution of unequal signals

Phase Noise


18/3416

3131sa

Specifications

Resolution: RBW Determines Measurement Time

Penalty For Sweeping Too FastIs An Uncalibrated Display

Swept too fast

3232sa

Specifications

Resolution: Digital Resolution BW

Typical SelectivityAnalog 15:1 Digital 5:1

Analog Filter

Digital Filter


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3333sa

Lab : Measuring noise sidebands

Chanllenge

Measure the analysers

sideband noise

What you will learn

To think in term of od

dBm/Hz

Limit to close-in amplitudemeasurement range

3434sa

Specifications

Sensitivity/DANL

Sweep

LO

MixerRFInputRES BWFilter

Detector

A Spectrum Analyzer Generates and Amplifies Noise Just Like Any

Active Circuit


20/3418

3535sa

Specifications

Sensitivity/DANL

10 dB

Attenuation = 10 dB Attenuation = 20 dB

signal level

Effective Level of Displayed Noise is a Function of RF

Input Attenuation

Signal-To-Noise Ratio Decreases as

RF Input Attenuation is Increased

3636sa

Specifications

Sensitivity/DANL: IF Filter (RBW)

Decreased BW = Decreased Noise

100 kHz RBW

10 kHz RBW

1 kHz RBW

10 dB

10 dB

Displayed Noise is a Function of IF Filter

Bandwidth


21/3419

3737sa

Specifications

Sensitivity/DANL: VBW

Video BW Smoothes Noise for Easier Identification of

Low Level Signals

3838sa

Specifications

Sensitivity/DANL

Signal

Equals

Noise

Sensitivity is the Smallest Signal That Can Be

Measured

2.2 dB


22/3420

3939sa

Lab : Measuring Small Signal

Chanllenge

Measure a small signal

Measure the analyzers

noise/sensitivity

What you will learn

How small a signal can the

analyzer measure To set the analyzer for the

best sensitivity

4040sa

Specifications

Sensitivity/DANL

Narrowest Resolution BW

Minimum RF Input Attenuation

Sufficient Video Filtering(Video BW < .01 Res BW)

For Best Sensitivity Use:


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4141sa

Specifications

Distortion

Frequency TranslatedSignals

Signal ToBe Measured

Resultant

Mixer GeneratedDistortion

Mixers Generate Distortion

4242sa

Specifications

Distortion

Distortion Products Increase as a Function of

Fundamental's Power

Second Order: 2 dB/dB of

FundamentalThird Order: 3 dB/dB of Fundamental

3

f 2f 3f

Power

in dB

2

f f2f -f1 2 1 2

Power

in dB

33

2 12f - f

Two-Toned Intermod

Harmonic Distortion

Third-order distortion

Second-order distortion


24/3422

4343sa

Specifications

Distortion

Relative Amplitude Distortion Changes with input

power level

3

f 2f 3f

Power

in dB

221 dB

20 dB

4444sa

Specifications

Distortion:

Distortion is a Function ofMixer Level

Second Order

Third Order

TOI


25/3423

4545sa

Specifications

Distortion:

Pre-Selector

Or Low Pass

Filter

Crystal

Reference

Log

Amp

RF input

attenuator

mixer

IF filterdetector

video

filterlocal

oscillator

sweep

generator

IF gain

Input

signal

CRT display

1. Change Input

Attn by 10 dB

2. Watch Signal

on Screen

4646sa

Lab : Prevent bad analyzer measurements

Challenge

Set the analyzer so that its

measurements areaccurate

What you will learn

Prevent analyzer adding

distortion to the

measurements


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4747sa

Specifications

Dynamic Range

Dynamic

Range

4848sa

Specifications

Dynamic Range

S-N Ratio Can be graphed

Noise in a 1 kHz RBW

Noise in a 100 Hz RBW


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4949sa

Specifications

Dynamic Range

Dynamic Range Can be presentedgraphically

Max 2nd Order

Dynamic Range

Optimum Mixer Level

Max 3rd Order

Dynamic Range

TOI SOI

5050sa

Specifications

Dynamic Range

MDR3 = 2/3(DANL-TOI) MDR2 = (DANL-SOI)

Where TOI = Mixer Level dBc/2SOI = Mixer Level-dBc

Optimum Marker Level=DANL-MDRAttenuation=Signal-Optimum Mixer Level

Calculated Maximum Dynamic Range


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5151sa

Specifications

Dynamic Range

MDR3 = 2/3((-115)-(+5))= -80 dBc (1kHz RBW)

Where TOI = (-30) (-70)/2= + 5 dBm

Optimum Marker Level=(-115)-(-80)Attenuation=0-(-35) = +35 dBm

Example Calculation

5252sa

Lab : Find your analyzers dynamic range

Challenge

Given specification , use

the dynamic rangeequations to find theanalyzers best dynamicrange

What you learned

Use for dynamic rangegraphic and equations

Find performancedifferences between

analyzers


29/3427

5353sa

Specifications

Dynamic Range

Dynamic Range for Spur Search Depends on

Closeness to Carrier

Dynamic Range Limited

By Noise SidebandsdBc/Hz

Noise Sidebands

Dynamic Range LimitedBy Compression/Noise

Display Average Noise Level

5454sa

Specifications

Dynamic Range

ACTUAL DYNAMIC RANGE IS THE MINIMUM OF:

Maximum dynamic range calculation

Noise sidebands at the offset frequency

Calculated from:

-Distortion

-Sensitivity


30/3428

5555sa

Specifications

Dynamic Range

+30 dBm

-115 dBm (1 kHz BW & 0 dB ATTENUATION)

MAXIMUM POWER LEVEL

CRT-DISPLAY

RANGE80 dB

-10 dBm

-35 dBm

-45 dBm

INCREASING

BANDWIDTH OR

ATTENUATION

SECOND-ORDER DISTORTION

MIXER COMPRESSION

THIRD-ORDER DISTORTION

SIGNAL/NOISE

RANGE

105 dB

RANGE

145 dB

MEASUREMENT

MINIMUM NOISE FLOOR

70 dB RANGEDISTORTION

80 dB RANGE

DISTORTION

0 dBc NOISE SIDEBANDS

60 dBc/1kHz

SIGNAL /3rd ORDER

SIGNAL/ 2nd ORDER

SIGNAL/NOISE SIDEBANDS

5656sa

Agenda

Overview

Theory of Operation

Specifications

Measurements


31/3429

5757sa

Measurements

Viewing Signal

5858sa

Measurements

Improving Frequency Accuracy


32/3430

5959sa

Measurements

Saving a file

6060sa

Measurements

Loading a file


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6161sa

Measurements

Burst Power Measurements

6262sa

Measurements

CCDF (Complementary Cumulative Distribution Function )

Measurements


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6363sa

Measurements

Distortion



Resultant



6464sa

Measurements

Distortion



Resultant



01 Basic Spectrum Analysis 1_rev

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