7/28/2019 01 Basic Spectrum Analysis 1_rev
1/34
Basic Spectrum
Analysis
By
CSG Solution(Thailand) Ltd.
www.csgs.co.th
7/28/2019 01 Basic Spectrum Analysis 1_rev
2/34
Table of Contents
Overview Theory of Operation Specification Measurements
7/28/2019 01 Basic Spectrum Analysis 1_rev
3/341
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
4/342
33sa
Agenda
Overview
Theory of Operation
Specifications
Measurements
44sa
Overview
What is Spectrum Analysis?
8563ASPECTRUM ANALYZER 9kHz -26.5GHz
7/28/2019 01 Basic Spectrum Analysis 1_rev
5/343
55sa
Overview
Types of Tests Made
Modulation
Distortion
Noise
66sa
Overview
Frequency versus Time Domain
Amplitude
(power)
Time domain
MeasurementsFrequency Domain
Measurements
7/28/2019 01 Basic Spectrum Analysis 1_rev
6/344
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
8/346
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
9/347
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)
7/28/2019 01 Basic Spectrum Analysis 1_rev
10/348
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
11/349
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
12/3410
1919sa
Agenda
Overview
Theory of Operation
Specifications
Measurements
2020sa
Specifications
8563ASPECTRUM ANALYZER 9kHz -26.5GHz
Frequency Range
Accuracy, Frequency & Amplitude
Resolution
Sensitivity
Distortion
Dynamic Range
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
16/3414
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
19/3417
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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:
7/28/2019 01 Basic Spectrum Analysis 1_rev
23/3421
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
26/3424
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
27/3425
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
28/3426
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
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
7/28/2019 01 Basic Spectrum Analysis 1_rev
31/3429
5757sa
Measurements
Viewing Signal
5858sa
Measurements
Improving Frequency Accuracy
7/28/2019 01 Basic Spectrum Analysis 1_rev
32/3430
5959sa
Measurements
Saving a file
6060sa
Measurements
Loading a file
7/28/2019 01 Basic Spectrum Analysis 1_rev
33/3431
6161sa
Measurements
Burst Power Measurements
6262sa
Measurements
CCDF (Complementary Cumulative Distribution Function )
Measurements
7/28/2019 01 Basic Spectrum Analysis 1_rev
34/34
6363sa
Measurements
Distortion
Frequency TranslatedSignals
Signal ToBe Measured
Resultant
Mixer GeneratedDistortion
Mixers Generate Distortion
6464sa
Measurements
Distortion
Frequency TranslatedSignals
Signal ToBe Measured
Resultant
Mixer GeneratedDistortion
Mixers Generate Distortion
Top Related