Cascade Analysis Program


Cascade is a program for analyzing the noise and distortion performance of a cascade of elements in an electronic system. A typical application of cascade is the analysis of a receiver. A text description of the receiver block diagram consisting of things like amplifiers, mixers, and filters is entered into cascade. Each element is characterized by its gain and optionally noise figure, and third order intercept point. The program then analyzes the system and produces a report detailing the performance at each stage.

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Input File Format

Cascade reads a system description from a text file, computes the parameters for the system, and produces a report file. The input file is created using any ASCII text editor.


Any line beginning with *, #, or ; is treated as a comment line and is ignored. In addition, any line starting with @ is treated as a verbose comment line which is copied over to the output. This allows extra annotation to be added to the output file. Blank lines (lines with only spaces and tabs) are ignored.


An optional defaults line may be included to tell the program certain default parameters. The defaults line may be used anywhere in the input file. The listed values take effect at the place in the system where the defaults line is given. Multiple defaults lines may be used in the input file. This is useful if, for example, the system switches from 75 ohms to 50 ohms part way through the cascade.

A defaults line is specified as follows:


Some examples of valid defaults lines are:


An optional source line may be included to tell the program what the carrier level is going into the system. In addition, C/No, or equivalently, C/N and receiver noise bandwidth, may be specified to allow calculation of C/N degredation. If a source line is used, it must come before any element lines. A source is specified as follows:


Some examples of valid source lines are:

Element Lines

Each element in the system is described by an element line. The elements are connected in the order in which they appear in the input file. Elements are entered as follows:


Some examples of valid element lines are:

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This section shows an example of the use of the cascade program. The block diagram for the system to be analyzed is shown below.

Example Block Diagram

Example Input File

The input file ex1.cas contains the following:

Running Cascade

To run cascade on the input file and display the results to the screen, use the following format.


The results can be saved to a file by

Example Output

The resulting output file ex1.out contains the following:

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System Requirements

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Cascade is available for free but is not in the public domain. Please refer to the license file for details.

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Obtaining Cascade

Cascade is now hosted by SourceForge and can be downloaded via FTP at or via HTTP from

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Please refer to the file INSTALL that is part of the cascade distribution for details on installation.

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Reporting Bugs

To report a bug, request a new feature, or participate in an online discussion forum about cascade, please visit the project's SourceForge Home.

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