Vector Signal Generator
Arb and Real-Time Signal Generation
Arb and Real-Time Signal Generation
Purpose
• To describe the differences between Arbitrary waveform
generation (Arb) and real-time waveform generation
• To understand the difference between component test and
receiver test
• To experience the flexibility of Arb signals
• To demonstrate the similarities between Arb and real-time
waveforms
• To familiarize you with the external waveform creation tool
Signal Studio
Arb and Real-Time Signal Generation
Slide 2
Digital (I/Q) Modulation
Format Modes
The signal generator supports two types of baseband signal
generation:
• Arbitrary waveform playback (Arb) mode
¾ Commonly associated with component test
¾ Can also be used for receiver test
• Real-time mode
¾ Is typically associated with just receiver test
Arb and Real-Time Signal Generation
Slide 3
A Signal Generator Requirement
for Digital Modulation
To use either the ARB or Real-time features to create digital
modulation, a vector signal generator must have an internal baseband
generator (BBG):
Baseband Generator Options
Signal
Generator
Model
Opt 601
Opt 602
Opt 651
Opt 652
Opt 654
Opt 019
100 MSa/s
100 MSa/s
30 MSa/s*
60 MSa/s
125 MSa/s
64 MSa
8 MSa
64 MSa
8 MSa
8 MSa
8 MSa
E4438C
x
x
---
---
---
---
E8267D
x
x
---
---
---
---
---
---
x
x
x
x
N5162A/82A
Memory is important for playing Arb waveforms.
Arb and Real-Time Signal Generation
Slide 4
Arb Waveforms
• The Arb provides unlimited signal creation flexibility for a short
amount of time.
• Customers typically use signals that are less than one minute in
length.
Arb and Real-Time Signal Generation
Slide 5
Arb Waveforms
• Used for testing both system components (such as amplifiers)
and receivers.
• The signal generator generates a waveform and saves it to a
file, so the waveform has a finite length.
• The signal generator then plays this file once or multiple
times.
• The file can be stored on the signal generator and recalled for
use later.
Arb and Real-Time Signal Generation
Slide 6
Arb Waveforms
The Arb generates various I/Q waveform types:
• User defined—create your own waveform or develop new
modulation schemes
• Standardized modulation schemes (W-CDMA, cdma,
TD-CDMA, etc.)
Arb and Real-Time Signal Generation
Slide 7
Arb Waveforms
Some of the Arb waveform creation tools for standardized modulation
schemes do not incorporate all of the coding and framing typically
associated with these types of signals. These signal are used for
component testing.
Arb waveform creation tools that do
incorporate the coding and framing can be
used for both component and receiver tests.
Arb and Real-Time Signal Generation
Slide 8
Arb Waveforms
For the Arb waveforms that do not incorporate the coding and
framing, their signal is statistically equivalent to the fully coded and
framed signal.
Includes Coding and Framing
Arb and Real-Time Signal Generation
No Coding and Framing
Slide 9
Arb Waveform Creation Tools
The signal generator supports waveforms from both internal and
external signal creation tools.
Embedded (Internal) Tools
Optional signal generator features that allow the signal generator
to both create and play waveforms. Typically 4xx series of options.
The BBG option also includes these
tools:
•
Custom—waveform creation tool
(E4438C & E8267D)
•
Dual ARB Player—only plays
waveforms (E4438C, E8267D,
N5162A/82A)
Arb and Real-Time Signal Generation
400 W-CDMA
401 cdma2k
Slide 10
Arb Waveform Creation Tools
External Tools
This refers to software tools used to create the waveform and then it is downloaded
to the signal generator for playback. The signal generator still requires a BBG to
store and play the waveforms.
Typically N76xxA/B Model Number (requires license purchase)
• N7600B W-CDMA HSPA
• N7613A WiMAX
EEsof ADS Connected Solutions
Other Software Tools
• C++
• MATLAB
• Visual Basic
Arb and Real-Time Signal Generation
• Agilent VEE
Slide 11
Arb Block Diagram
Internal arbitrary waveform generator block diagram (option 602)
Signal Studio
or
Customer File
Waveform memory
BBG Memory in the MXG
Filter
16
DSP
I RAM
64 MSa
16
16
Over sampling
16
DAC
Data
Generator
I
To
I/Q modulator
Filter
Q RAM 16
64 MSa
16
Over sampling
16
DAC
Q
16
Signal Studio
or
Customer File
Arb and Real-Time Signal Generation
Waveform memory
BBG Memory in the MXG
Slide 12
Real-Time Signals
Real-time signal creation tools do just what the name implies,
they create the signal in real-time. There is no stored file, nor is
the signal finite in length.
Real-time tools provide limited signal creation flexibility for a
long period of time. The modulation types are fixed.
Customers may use signals that are minutes to hours long.
Arb and Real-Time Signal Generation
Slide 13
Real-Time Signal Channel Coding
Signals created for standardized modulation schemes (TDMA,
cdma, W-CDMA, etc.) are fully coded and framed.
Since the signals are fully coded, they can be
used to test the entire receiver side of a system.
Great for BER testing.
Arb and Real-Time Signal Generation
Slide 14
Real-Time Block Diagram
Customer
User File
(6.4MB)
Repeated
indefinitely
Created in DSP and continuously
streamed to DAC
16
Data
Generator
16
DAC
I/Q
Symbol
Builder
Built-in data
patterns
16
External
Data input
Arb and Real-Time Signal Generation
Over sampling
Filter
Filter
Over sampling
16
DAC
I
Q
Infinite data length
Use for BER and BLER testing
Slide 15
Real-Time Signal Creation Tools
Real-time (RT) signal creation tools also include both embedded and
external products.
Embedded Tools
Just like the Arb, there are optional signal generator features that allow
the signal generator to create real-time signals. Typically 4xx series of
options.
(A 4xx option can contain both RT & Arb tools)
400 W-CDMA
401 cdma2k
The BBG option also includes this tool:
• Custom—signal creation tool (E4438C &
E8267D)
The N5162A/82A MXG supports only two real-time capabilities: Option 403 AWGN
and Option 432 Phase Noise.
Arb and Real-Time Signal Generation
Slide 16
Real-Time Signal Creation Tools
External Tools
The signal generator still requires a BBG to create the signals.
Typically N76xxA/B Model Number (requires license purchase)
(A signal studio product is either real-time or Arb based.)
Other Software Tools
•
C++
• MATLAB
• Visual Basic
• Agilent VEE
Embed SCPI commands in the code to
create the signal.
Arb and Real-Time Signal Generation
Slide 17
Summary
Arb
• Used for both component and receiver testing.
• Provides unlimited signal creation flexibility for a short
amount of time.
Real-Time
• Primarily used in receiver testing.
• Provides limited signal creation flexibility for a long
amount of time.
For information about signal creation tools (embedded and external) visit:
www.agilent.com/find/signalstudio
Arb and Real-Time Signal Generation
Slide 18