Audio and Data module system

In MODCOM-7 some of the techniques of transmitting digitaldata currently used in modern digital communications systems are studied. A digital information signal is conveyed on to a carriersignal whose instantaneous amplitude or angle varies accordingto the variation of the original information signal.Specifically, Quadrature Amplitude Modulation (QAM) and M-ary PhaseShift Keying (PSK) are studied and compared. Carrier recovery, symbol synchronization and equalization arealso covered by experiments.The telephone line is studied as a medium of transferring data,as well as common disturbances such as channel fading and multipath effects.The transmitting modem, receiving modem and channel are simulated by specially developed software that runs in the MS-Windows environment. The simulations are interactive, allowing the student to vary various parameters and modes of operation.The student measures the performance at the various modems and communication channels by operating measuring instruments such asbit error rate (BER) meter, and graph display for time and spectrumthat are also simulated on the personal computer.Module DescriptionThe Voiceband modem, Synchronization and Voice Band Channel simulation software module, MODCOM-7, consists of the following:Constellation synthesizer QAM modulator QAM demodulator Carrier recovery Symbol synchronization Decision feedback equalizer (DFE) Bit error rate (BER) meter Voiceband channelRecommended Experiments1. Quadrature Amplitude Modulation 2. Comparison of 8-PSK with 8-QAM3. Using the telephone line for transmitting Data 4. Carrier recovery and symbol synchronization5. Equalization6. Fading and Multipath Channels