Technical data

9-2
Understanding the CITIfile Data Format
Introduction
Introduction
This chapter explains the use of the CITIfile (Common Instrumentation Transfer and Interchange file)
format for the storage and transfer of measurement and data information. Several examples of CITIfiles
have been included in this chapter to demonstrate how the format can used to simplify the transfer of
measurement and data information between instruments and computers. For many data processing
applications, the S2P file (filename.S1 and filename.S2) may provide a more convenient format.
The CITIfile Data Format
CITIfile is a standardized data format, used for exchanging data between different computers and
instruments. CITIfile is an abbreviation for "Common Instrumentation Transfer and Interchange file". This
standard has been a group effort between instrument designers and designers of computer-aided design
programs. As much as possible, CITIfile meets current needs for data transfer, and it was designed to be
expandable so it can meet future needs.
CITIfile defines how the data inside an ASCII package is formatted. Since it is not tied to any particular disk
or transfer format, it can be used with any operating system (BASIC, DOS, UNIX, etc.), with any disk
format (LIF, DOS, HFS, etc.), or with any transfer mechanism (disk, LAN, GPIB, etc.). By careful
implementation of the standard, instruments and software packages using CITIfile are able to load and
work with data created on another instrument or computer. It is possible, for example, for a network
analyzer to directly load and display data measured on a scalar analyzer, or for a software package running
on a computer to read data measured on a lightwave component analyzer.
Data Formats
There are two main types of data formats: binary and ASCII. CITIfile uses the ASCII text format. While this
format does take up more bytes of space than a binary format, ASCII data is a transportable, standard type
of format which is supported by all operating systems. In addition, the ASCII format is accepted by most
text editors. This allows files to be created, examined, and edited easily, making CITIfile easier to test and
debug.
File and Operating System Formats
CITIfile was designed to be independent of the data storage mechanism, and therefore may be
implemented for any file system. However transfer between file systems may sometimes be necessary. Any
commercially available software that has the ability to transfer ASCII files between systems may be used to
transfer CITIfile data.
Definition of CITIfile Terms
This section will define the following terms:
• package
•header
• data array
•keyword