Intermodulation Products Module

SoftWright’s Intermodulation Products Module can be used as a stand-alone package or integrated with other programs in the TAP software system. The Intermodulation module provides programs needed in establishing and maintaining multi-user radio communication sites. Intermodulation study programs provide analytical and diagnostic tools for locating actual interference sources as well as predicting potential intermodulation interference problems before new facilities are built.

Capabilities of the TAP Intermodulation Products Module include:
Enter Frequencies - You can enter thousands of transmitted frequencies and received frequencies used at your radio sites. The entered frequencies are saved in a file for repeated future use, along with an identifier, such as a call sign or user name. An editor is provided to key in these frequencies into the database. You can also import data from EXCEL™, Access™ or ASCII files into the fixed facility database in the software.

Specify Transmitter Harmonics - For each transmit frequency, enter the number of harmonics (up to ninth order) to consider as possible participating component frequencies. The use of this option will significantly reduce superfluous output predictions that are not likely to be actually generated. Typically lower powered transmitters are considered only to the 2nd or 3rd harmonic. Higher-powered transmitters might be considered up to the 7th or 9th order harmonic in the most conservative of circumstances.

Information can be entered and edited through user-friendly data entry screens.

Specify Transmitter Deviation - For each transmitted frequency, enter a specified deviation. This will permit the inclusion of possible intermod hits resulting from combined modulated carriers (the narrow bandwidth spectrum surrounding the carrier frequency which contains the modulation.) This significantly improves the diagnostic and predictive value of intermod studies.

Specify Transmitter Groups - This option permits you to assign a group number to transmitter facilities; for example, when you are seeking one new transmit frequency to be added to a site and four transmitting frequencies are being considered, include all four and assign the same group number to each. The program will disregard any hits that would result from any of the four frequencies combining since you propose to assign only one of them. This eliminates the need to run and evaluate four separate intermod studies.

Specify Receive Offset Protection - For each protected (receive) frequency, enter a specified offset for intermodulation protection. This will limit the generated results database information to only those possible products that are predicted to occur within the specified protected bandwidth around protected frequencies. The offset can be as narrow as 0.01Hz or as wide as 999.999 MHz and is independently specified for each protected frequency. The offset you specify is generally a function of channel spacing, modulation deviation, injected sub-carrier frequencies and desired guard band around the protected frequency.

Intermod Study Program - Your frequency database is manipulated to calculate the predicted intermod products. You can consider the combination of up through four participating component frequencies and up to the 99th order of intermod product being generated. Predicted products can be inclusive of all transmitted frequencies and their respective harmonics combining with each other to predict all possible products. Another option permits you to limit your study to only those hits, which are generated as a result of a certain specified frequency. This feature is particularly helpful when you are considering the addition of new transmitter frequencies to an existing site. You might wish to limit the scope of your compatibility study to those hits, which are a possible direct result of only those new frequencies combining together and with the existing frequencies at the site.

Report Generator - The results database created, when you run particular studies, can then be filtered and sorted using many options. Typical sorts can be on the frequency of the computed intermod product or ranges of order of intermod products. This feature simplifies the identification of potential intermod problems with the receivers at the site.

Output File Export - Using the report generator will also permit you to export the calculated results to comma or tab delimited files. This provides unlimited flexibility to permit sorting and graphical analysis using EXCEL™, Access™ or many other widely used spreadsheets and graphical plotting software, without having to rerun the calculations each time.

Eliminate Simplex Products - Simplex systems (with the same transmit and receive frequencies) are recognized to eliminate false products involving the transmitter with its own receiver.

Documentation - A detailed written tutorial is provided on how to run the software. An extensive technical reference is also included to assist in the practical prevention, diagnosis and treatment of actual intermodulation products. The documentation is also available on-line in the software.

Import FCC Database into TAP - In order to eliminate the manual data entry of authorized facilities you may import data from the FCC frequency databases using  Percon Corporation or other frequency databases that support the file exchange format for FCC Databases.

 

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Copyright 2005 by SoftWright LLC