Agenda

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# Agenda - PowerPoint PPT Presentation

Agenda. Types of sources CW Swept Signal Generator Block Diagrams Applications Specifications. Sources Generate Sine Waves. Voltage. Time. Frequency. Voltage. Spectrum Analyzer. Oscilloscope.

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Presentation Transcript
Agenda
• Types of sources
• CW
• Swept
• Signal Generator
• Block Diagrams
• Applications
• Specifications

Source Basics

Sources Generate Sine Waves

Voltage

Time

Frequency

Voltage

Spectrum Analyzer

Oscilloscope

This is the ideal output: most specs deal with deviations from the ideal and adding modulation to a sine wave

Millimeter

RF

Microwave

3-6 GHz

20-50 GHz

300 GHz

Source Basics

Types of Sources
• CW
• generates a single frequency, fixed sine wave
• Swept
• sweeps over a range of frequencies
• may be phase continuous
• Signal Generator
• produces “real world” signal

Source Basics

Types of sources

• CW
• Swept
• Signal Generator
• Block Diagrams
• Applications
• Specifications

Agenda

Source Basics

CW Source Specifications

...Frequency

t

+

+

t

f

_

_

cal

aging

CW

f

CW

t

aging

t

cal

Accuracy = 152 Hz

• Range: Range of frequencies covered by the source
• Resolution: Smallest frequency increment.
• Accuracy: How accurately can the source frequency be set.

EXAMPLE

Accuracy =

= CW frequency = 1 GHz

= aging rate = 0.152 ppm/year

= time since last calibrated = 1 year

*

*

Uncertainty

Voltage

Frequency

Source Basics

CW Source Specifications

...Amplitude

• Range (-136dBm to +13dBm)
• Accuracy (+/- 0.5dB)
• Resolution (0.02dB)
• Switching Speed (25ms)
• Reverse Power Protection

Source protected from accidental transmission from DUT

What is P out?

How accurate is this number?

max

DUT

Voltage

min

What is P out?

Frequency

Source Basics

Phase Noise

Residual FM

Spurious

CW Source Specifications

...Spectral Purity

CW output

Residual FM is the integrated phase noise over 300 Hz - 3 kHz BW

harmonic spur

~30dBc

phase noise

non-harmonic spur

~65dBc

sub-harmonics

0.5 f0 f02f0

Source Basics

CW Source Specifications

... Spectral Purity: Phase Noise

CW output

measured as dBc/Hz

Power Spectral Density

frequency

Ch1 PM PSD

TRACE A:

A Marker

10 000 Hz

75 dBc/Hz

LogMag

5 dBc/div

-105 dBc/Hz

-125 dBc/Hz

1k

10k

100k

Source Basics

RF CW Block Diagram

Synthesizer Section

Frac-N

Output Section

Output

Attenuator

ALC Modulator

f

Phase

Detector

VCO

ALC

Driver

divide

by X

Reference

Oscillator

ALC Detector

Reference Section

ALC = automatic level control

Source Basics

RF CW Block Diagram

Reference Section

divide

by X

TCXO

OCXO

Aging Rate

+/- 2ppm/year

+/- 0.1 ppm /year

Temp.

+/- 1ppm

+/- 0.01 ppm

Line Voltage

+/- 0.5ppm

+/- 0.001 ppm

to synthesizer section

f

Phase

Detector

Optional External Reference Input

Reference Oscillator (TCXO or OCXO)

Source Basics

RF CW Block Diagram

Synthesizer Section

...produces accurate, clean signals

N = 93.1

Front panel

control

Frac-N

5MHz

to output section

f

X 2

Phase

Detector

931 MHz

VCO

multiplier

5MHz

465.5 MHz

from reference section

Source Basics

RF CW Block Diagram

Synthesizer Section

frequency

PLL / Fractional - N

...suppresses phase noise

phase noise of source

phase-locked-loop (PLL) bandwidth selected for optimum noise performance

noise

reference

oscillator

phase detector noise

20logN

VCO noise

Source Basics

RF CW Block Diagram

Output Section

Output

Attenuator

ALC Modulator

from synthesizer section

source output

ALC

Driver

ALC Detector

• ALC
• maintains output power by adding/subtracting power as needed
• Output Attenuator
• mechanical or electronic
• provides attentuation to achieve wide output range (e.g. -136dBm to +13dBm)

ALC = automatic level control

Source Basics

mWave CW Block Diagram

Output

Attenuator

ALC Modulator

ALC

Driver

Reference Section

Frac

N

Phase

Det

f

VCO

Sampler

by X

Ref Osc

YIG

Oscillator

f

Phase

Detector

Tuning

Coils

Frac-N

Synthesizer Section

ALC Detector

f

Phase

Detector

Output Section

VCO

Source Basics

Applications & Critical Specifications
• Local Oscillator
• phase noise
• frequency accuracy
• Amplifier Distortion
• spurious
• TOI (for system)
• Spurious
• spurious
• level accuracy

Source Basics

Applications & Critical Specifications

As a Local Oscillator

IF signal

transmitter output

DUT

poor frequency accuracy will cause transmitter to be at the wrong frequency

Source Basics

Applications & Critical Specifications

Amplifier Testing

f1

DUT

output RF

f2

isolator

Intermodulation

Distortion

f1

f2

test system third order products will also fall here

spurious signals from source can corrupt measurement

amplitude

fL = 2f1 - f2

fU = 2f2 - f1

frequency

Source Basics

Applications & Critical Specifications

in-channel signal

(modulated signal)

IF signal

out-of-channel signal

(CW or modulated signal)

DUT

source output

IF Rejection Curve

spur from source and/or high levels of phase noise can cause a good receiver to fail

Level (dBm)

Frequency

Source Basics

Agilent Families of CW Generators

RF

Agilent 8662/63 family

• 100 KHz - 2.5 GHz
• Low in channel noise
• AM/FM/Phase/Pulse

Agilent 8664/65 family

• 100 MHz - 6 GHz
• Low out channel noise
• AM/FM/Pulse.

Microwave

Agilent 83711/12B family

• 10 MHz - 20 GHz
• CW only

Source Basics

Agenda
• Types of sources
• CW
• Swept
• Signal Generator
• Block Diagrams
• Applications
• Specifications

Source Basics

Sweeper Specifications

...Frequency

• ramp sweep
• accuracy
• sweep time
• resolution

f2

frequency

f1

t2

t1

time

• step sweep
• accuracy
• number of points
• switching time

f4

f3

frequency

f2

f1

t1

t2

t3

t4

Source Basics

Sweeper Specifications

...Amplitude

level accuracy spec

power

flatness spec

f1

f2

frequency

}

P2

power sweep range

power

P1

t1

t2

Frequency Sweep

• Level Accuracy
• Flatness
• Source Match (SWR)Power Sweep
• Power Sweep Range
• Power Slope Range
• Source Match (SWR)

Source Basics

Applications & Critical Specifications
• Frequency Response
• Frequency Accuracy
• Output Power (Level) Accuracy
• Flatness
• Speed
• residual FM
• Amplifier Compression
• Power Range

Source Basics

Applications & Critical Specifications

Frequency Response Testing

Sweeper Input

• Frequency Accuracy
• Output Power (Level) Accuracy
• Flatness
• Speed
• residual FM

LO

Source Basics

Applications & Critical Specifications

Frequency Response Testing

Log Mag

5.0 dB/

Ref -15.00 dB

1:Transmission

BW: 429.600 MHz

CF: 2405.782 MHz

5

dB

Q: 5.60

Loss: -0.84 dB

1

0

-5

3

5

6

-10

Ch1

-20

-25

-30

1

-35

Abs

Center 2 450.212 MHz

Span 1 099.577 MHz

Source Basics

Applications & Critical Specifications

Amplifier Compression

1 dB compression

point

Power Out

Power In

• Power Range

The 1 dB compression point is a common amplifier specification used to identify the linear operating range of an amplifier. Power sweep is available on some Agilent sources.

Source Basics

Synthesized Sweep Generators
• Agilent 83750 Series
• Step/Analog sweep
• AM/FM/Phase modulation
• 10MHz to 20GHz
• up to 110GHz with 83550 series
• modules and amplifier
• Agilent 8360L Series
• Step/Analog sweep
• 8510/8757 Compatibility
• 10MHz to 50GHz
• up to 110GHz with 83550 series

modules

Source Basics

Agenda
• Types of sources
• CW
• Swept
• Signal Generator
• Block Diagrams
• Applications
• Specifications

Source Basics

Signal Generators
• Calibrated modulation
• Analog (AM, FM, PM, Pulse)
• Digital (I-Q)
• Format Specific(TDMA,CDMA, etc.)

Source Basics

Modulation

...Where the information resides

p

f

V= A(t) sin[2 f(t) + (t)]

AM, Pulse

PM

FM

V= A(t) sin[ (t)]

q

Source Basics

Modulation: Analog

Amplitude Modulation

Carrier

Important Signal Generator Specs for Amplitude Modulation

Voltage

Time

• Modulation frequency
• Linear AM
• Log AM
• Depth of modulation (Mod Index)

Modulation

Source Basics

Modulation: Analog

Frequency Modulation

F /F

Important Signal Generator Specs for Frequency Modulation

b = D

dev

mod

p

b

V= A sin[2 f t + m(t)]

c

• Frequency Deviation
• Modulation Frequency
• dcFM
• Accuracy
• Resolution

Voltage

Time

Source Basics

Modulation: Analog

Phase Modulation

V= A sin[2 p f t + m(t)]

Important Signal Generator Specs for Phase Modulation

• Phase deviation
• Rates
• Accuracy
• Resolution

b

c

b = Df

peak

Voltage

Time

Source Basics

Modulation: Analog

Pulse Modulation

Important Signal Generator Specs for Pulse Modulation

• Pulse width
• Pulse period
• On/Off ratio
• Rise time

T

Rate=1/T

Rise

time

Power

On/Off ratio

t

Time

Pulse

Width

1/T

1/t

Power

Source Basics

Digital Modulation

...signal characteristics to modify

Amplitude

Frequency

Phase

Both Amplitude

and Phase

Source Basics

Digital Modulation

Polar Display: Magnitude & Phase Represented Together

Mag

Phase

0 deg

• Magnitude is an absolute value
• Phase is relative to a reference signal

Source Basics

Digital Modulation

Signal Changes or Modifications

Mag

Phase

Phase

0 deg

0 deg

Magnitude Change

Phase Change

0 deg

0 deg

Both Change

Frequency Change

Source Basics

Digital Modulation

...Binary Phase Shift Keying (BPSK)

V= A sin[2 ft + (t)]

f

1

f

2

f

p

f

(t) =

Source Basics

Digital Modulation

BPSK IQ Diagram

Q

1

0

I

One Bit Per Symbol

Symbol Rate = Bit Rate

Source Basics

Digital Modulation

V= A sin[2 ft + (t)]

f

p

1 = 3 /4

f

(t) =

f

p

2 = /4

f

p

3 = - /4

f

p

4 = - 3 /4

p

f

Source Basics

Digital Modulation

QPSK IQ Diagram

Q

01

00

I

11

10

Source Basics

Digital Modulation

p/4 DQPSK IQ Diagram

Q

I

Source Basics

Digital Modulation

Modulation Accuracy

Magnitude Error (IQ error mag)

Q

{

Error Vector

Test

Signal

f

Ideal (Reference) Signal

Phase Error (IQ error phase)

I

Source Basics

Digital Signal Generator Block Diagram

IQ Modulator

• modulation quality

Baseband Generator

• modulation quality
• supported modulation formats

to output section

reference section (supplies timing)

Source Basics

Digital Modulation

PSK Implementation: IQ Method

I:

Carrier

p/2

Q:

• Good Interface with Digital Signals and Circuits
• Can be Implemented with Simple Circuits
• Can be Modified for Bandwidth Efficiency

Source Basics

Digital Signal Generator Block Diagram

IQ Modulator

DAC

DAC

I from Baseband Generator

Ext I

to output section

from synthesizer section

p/2

Q from Baseband Generator

Ext Q

Source Basics

Digital Signal Generator Block Diagram

Baseband Generator

From CPU

Pattern RAM

DAC

Constellation Map and Baseband Filters

I

Data

DAC

Q

Timing

Data Clock

Symbol Clock

Analog Reconstruction Filters

Source Basics

Digital Signal Generator

Format Specific Digital Signals

Parameter

Specification

Access Method

TDMA/FDD

Modulation

p/4 DQPSK

Channel Bandwidth

30 kHz

Reverse Channel

Frequency Band

824 - 849 MHz

Forward Channel

Frequency Band

869 - 894 MHz

Filtering

0.35 RRC

Source Basics

Digital Signal Generator

Access and Framing

one frame = 1944 bits (972 symbols) = 40ms; 25frames/sec

slot 1 slot 2 slot 3 slot 4 slot 5 slot 6

324 bit (162 symbols) = 6.667ms

G R Data Sync Data SACCH CDVCC Data

6 6 16 28 122 12 12 122

Mobile to Base Station

Source Basics

Applications and Critical Specifications

Analog and Digital

• frequency accuracy
• level accuracy
• error vector magnitude
• phase noise
• spurious
• spectral accuracy
• Spectral Regrowth
• ACP performance

Source Basics

Applications and Critical Specifications

frequency inaccuracy

amplitude inaccuracy

Want to measure

sensitivity in a channel

Measurement impaired by

frequency inaccuracy

input for signal generator

DUT

• Frequency Accuracy

Source Basics

Applications and Critical Specifications

• Level Accuracy

Customer is testing a -110 dB sensitivity pager:

X= Failed unit

O=Passed unit

Power Out

Power Out

-110 dB specification

X

-110 dB specification

X

X

X

Set source to -111 dBm

X

X

X

Actual output power= -114 dBm

O

O

Actual output power= -112 dBm

O

O

Set source to -115 dBm

O

Frequency

Frequency

Case 1: Source has +/-5 dB of

output power accuracy at

-100 to -120 dBm output power.

Case 2: Source has +/-1 dB of

output power accuracy at

-100 to -120 dBm output power.

Source Basics

Applications and Critical Specifications

e.g. TETRA Signal

/4 DQPSK

EVM < 1.0%

Error Vector

p

• Error Vector Magnitude (EVM)

Source Basics

Applications and Critical Specifications

in-channel signal

(modulated signal)

IF signal

out-of-channel signal

(CW or modulated signal)

DUT

IF Rejection Curve

spur from source and/or high levels of phase noise can cause a good receiver to fail

Level (dBm)

Frequency

• Phase Noise
• Spurious

Source Basics

Applications and Critical Specifications

GSM Signal

0.3GMSK

Spectral Accuracy:

• EVM
• ACP

Source Basics

Applications and Critical Specifications

Spectral Regrowth

DUT

• ACP Performance

Output from amplifier

Input from signal generator

Source Basics

Agilent Families of Signal Generators

RF

Agilent ESG family

• 250 KHz - 4 GHz
• AM/FM/Phase/Pulse
• Digital/I-Q Mod
• GSM,CDMA,DECT...

Agilent 8647/48 family

• 9 KHz - 4 GHz
• AM/FM/Phase
• Paging, SMR, Cordless

Microwave

Agilent 8360B family

• 10 MHz - 50 GHz
• AM/FM/Pulse
• 110 GHz with ext. module

Agilent 83730 family

• 10 MHz - 20 GHz
• AM/FM/Pulse

Source Basics

Agenda

• Types of sources
• CW
• Swept
• Signal Generator
• Block Diagrams
• Applications
• Specifications

Source Basics