The voice band modem and channel software package will simulate the transmitting modem, the receiving modem and channel and will run under the MS-WINDOWS environment. The simulations should be interactive, allowing the student to vary various parameters and modes of operation. The student should be able to measure the performance of the various modems and communication channels by operating measuring instruments, and graph display for time and spectrum that will also simulated on the personal computer.
GRAPHIC INTERFACE
The graphical interface will consist of the graphics of the Modem structure, Menu for control of the Modem parameters, and Measuring Instruments.
The following features should be included:
· Block Diagram of the whole system.
· Inactive blocks shown extinguished.
· Control of the parameters of the functional blocks and their activation
· Display of the sub-block diagrams.
· Interactive definition of Active and Inactive functional blocks
· Measuring Instruments activation in different points on the functional blocks
· Transfer of the measurements done by the built-in measuring instruments to the appropriate field in the courseware
· Modem running according to initialized parameters defined by the user
GRAPHIC INTERFACE INITIALIZATION MENU
This includes the following functions:
-RUN- Modem Running
-NUMBER OF SYMBOLS- N=up to 5000 symbols
-SAVE- Files Save
-SYMBOL RATE- Symbol Transmission Rate
-STEP- Displays one of data vector symbols on the built in measuring equipment
The voice band modem and channel module consist of the following main blocks:
- Information Source with variety of Bit and Symbol Rates.
- constellation synthesizer
- transmit filter
- voice-band channel
- receiver filter
- symbol synchronization
- carrier recovery
- decision-feedback equalizer
MEASURING EQUIPMENT
The built-in measuring equipment can be dragged to the selected test point. A number of measuring instruments can be connected at the same time to a specific test point; alternatively, a measuring tool of graph\scope type can be connected to different points at the same time.
The data vectors displayed by the built-in measuring equipment will be provided by the Algorithm software and have max. length of: n=10-5000, while "n" should define the length of the data vector.
The interface software will apply to the data vector for the data display.
1. -Graph elements with Zoom as an option and scales for measurements performance (x4)
1.1-Time Domain signals including appropriate scales display.
1.2- Frequency Domain signals including appropriate scales display.
2. - Display dots on a Graph according X, Y Co-ordinates and appropriate scales.
3. - "Data" element for Numerical values display up to 4 numbers
4. - BER-METER-Device with numerical display for the following 4 fields:
4.1-Total Symbols=1000-1,000,000-shall
