Agilent Technologies E4445A User Manual

298 Chapter 5
Programming Fundamentals
Improving Measurement Speed
Programming Fundamentals
your numerical data queries. You may need to swap the byte order if
you are using a PC rather than UNIX. NORMal is the default byte order.
Use :FORMat:BORDer SWAP to change the byte order so that the least
significant byte is sent first. (Real,32 which is smaller and somewhat
faster, should only be used if you don’t need full resolution for your
data. Some frequency data may require full 64 bit resolution.)
When using the binary format, data is sent in a block of bytes with an
ASCII header. A data query would return the block of data in the
following format: #DNNN<nnn binary data bytes>
To parse the data:
• Read two characters (#D), where D tells you how many N characters
follow the D character.
• Read D characters, the resulting integer specifies the number of data
bytes sent.
• Read the bytes into a real array.
For example, suppose the header is #512320.
• The first character/digit in the header (5) tells you how many
additional digits there are in the header.
• The 12320 means 12 thousand, 3 hundred, 20 data bytes follow the
header.
• Divide this number of bytes by your current data format (bytes/data
point), 8 for real,64. For this example, there are 1540 data points in
the block of data.
Minimize the number of GPIB transactions.
When you are using the GPIB for control of your instrument, each
transaction requires driver overhead and bus handshaking, so
minimizing these transactions reduces the time used.
You can reduce bus transactions by sending multiple commands per
transaction. See the information on “Putting Multiple Commands on
the Same Line” in the SCPI Language Basics section.
If you are using the
MEASURE key measurements and are making the
same measurement multiple times with small changes in the
measurement setup, use the single READ command. It is faster then
using INITiate and FETCh.
Avoid unnecessary use of *RST.
Remember that while *RST does not change the current Mode, it
presets all the measurements and settings to their factory defaults.
This forces you to reset your analyzer’s measurement settings even if
they use similar mode setup or measurement settings. See Minimize
DUT/instrument setup changes. below. (Also note that *RST may put
the instrument in single measurement/sweep for some modes.)

Agilent Technologies E4445A Specifications

General

Brand	Agilent Technologies
Model	E4445A
Category	Measuring Instruments
Language	English

Summary

2. Instrument Functions: A − L

Marker Functions

Manages markers for trace analysis: Normal, Delta, Span Pair, Off, Marker Trace, Readout.

MEASURE Functions

Displays measurement menu for transmitter power, ACP, OBW, and distortion measurements.

MODE and Mode Setup

Selects measurement mode and configures common settings across measurements.

Peak Search Functions

Places marker on highest peak and displays search menu with parameters like Threshold and Excursion.

Preset Functions

Provides actions for instrument state reset: User, Mode, Factory presets, and Save User Preset.

SPAN / X Scale Functions

Activates Span function and displays menu for Span, Span Zoom, Full Span, Zero Span, Last Span.

SWEEP Functions

Controls sweep time, mode (continuous/single), auto sweep time, and gate parameters.

5 Programming Fundamentals

SCPI Language Basics

Introduces SCPI programming language, keywords, syntax, and parameters.

Improving Measurement Speed

Provides tips to make programs run faster, such as turning off display updates and using binary format.

Using the LAN to Control the Instrument

Details on configuring and controlling the instrument using LAN, including FTP, Telnet, Socket LAN, SICL.

Programming in C Using the VTL

Provides basic information about programming in C language using Agilent VTL (VISA transition library).

6 Using the STATus System

Status System Commands

Lists IEEE (*) Commands and STATus Commands for instrument status monitoring.

Using the Status Registers

Explains the PSA instrument status registers, their hierarchy, and how to use them.

7 Menu Maps: Spectrum Analysis

AMPLITUDE Y Scale Key

Menu maps for AMPLITUDE Y Scale functions, covering Reference Level, Attenuation, Scale, Presel, Corrections.

Auto Couple Key

Menu maps for Auto Couple, covering Auto All, FFT & Sweep, Detector, Avg/VBW Type, ADC Dither/Ranging.

BW/Avg Key

Det/Demod Key

Display Key

File Key

FREQUENCY Channel Key

Input/Output Key

Marker Key

Accesses marker control menu: Normal, Delta, Delta Pair, Span Pair, Off, Marker Trace, Readout.

Marker --> Key

Marker Fctn Key

MODE Key

Peak Search Key

Places marker on highest peak and displays search menu with parameters like Threshold and Excursion.

Preset Key

Provides actions for instrument state reset: User, Mode, Factory presets, and Save User Preset.

SPAN X Scale Key

SWEEP Key

System Key

Trig Key