Automated Distortion Characterization and Information System

Overview of Typical System

There is a growing need to perform automated distortion measurements and be able to record and track these results along with other test conditions. The data should be easily retrievable by various parameters such as date, product, description, test identifier, etc. This data must be able to be exported to other utilities and applications for analysis and graphing. Described below is a basic software system that has been developed to offer these capabilities. It can be customized to your needs and environment at a fraction of the cost and delay of developing a new system. You maintain the capability to alter the downloadable programs, modify or add reports in Microsoft Access, configure different options through initialization files, or output results to spreadsheets or word processors.

1. Block Diagram of a Typical Distortion Test Configuration Screen

(Optional – custom integrated systems)

The above screen is a typical DTS software control panel representing the block diagram of the system that is used to control the components of the Distortion Test System. The diagram will represent the hardware that is ordered for a given system and will be customized to each customer's requirements.  It is not necessary for running the Distortion Characterization System. It allows switching states by clicking on a relay in the block diagram to interconnect the various signal sources, amplifiers, filters, and measuring instruments. It is tightly integrated with the Matrix CATV Control Program to control the functions of the ASX generator. It also permits selection of filters, and provides an interface to automated distortion testing and database storage and retrieval functions. The distortion testing functions are selected by clicking on the Distortion Test button on the bottom of the screen above. These functions and the series of interactive screens are described below:

2. Test Profile Form

• Defines and maintains a profile of a test.
• An identification number (Test Id) is automatically assigned for a new test.
• Specify the group of frequencies to be used for a test measurement (See Test Frequency Selection Form).
• Enter information about the conditions under which the tests are conducted, i.e. Date, Test Description, and Notes, etc..
• Direct how the tests will be conducted -- (e.g. CSO Above Carrier, or both Above and Below the carrier).
• Specify bandwidth for compensating for Carrier to Noise (C/N) measurements
• Select method to perform the test, -- with a spectrum analyzer, or with an FFT
• Enter multiple criteria for setting up tests by using different Test Sub Id's. Criteria such as Carrier levels, Tilt, and the point of measurement (e.g. "After 3 cascaded amplifiers").
• Duplicate function to clone descriptions from a previous test when defining a new test.