Introduction:

The objective of this lab is to study and simulate a digital baseband modulation transmitter by using MATLAB software. In this lab, we will learn how to generate the transmitted baseband. In addition, there are different type of pulse shaping technologies. The main purpose of this lab is to understand the spectrum of transmitted signal, and to investigate the frequency leak. In this lab, we will use pulses to transmit the digital data. in fact, On-Off keying is the simplest digital baseband modulation, and we will transmit a signal when the digital bit is 1. Also, there is nothing to transmit when digital bit is zero. Another type of baseband digital modulation is that the 2PAM. When digital bit is 1, we will transmit the positive pulse. Also, the zero in digital bit should be in negative pulse. the 4PAM is considering as a kind of digital modulation, and we can transmit more than one bit in this type of modulation.

Procedure:

We used MATLAB program, and rectangular shape to generate the transmitted signal. In the first step, we edit some errors when we got codes, and we plot the spectrum in correct side. In the second step, we had to delay the pulse at different time delay. The purpose of this step is to modulate different symbols. In the third step, we used the OOK and 4PAM to transmit them as modulation scheme. In the last step of this lab, we used Hamming and Hanning pulse shape to generate the baseband transmitted signals.

Results:

When we write a text in edit file, MATLAB will convert digital to binary numbers. Also, it will transmit the digital baseband modulation, and it will show some figures.

Conclusion:

In this lab, we learned how to transmit baseband, and we learned some types of digital baseband modulation. For OOK modulation, zero bit in binary number will transmit as zero, and 1 should be p(t). For PAM2, one bit will transmit as p(t), and zero should be -p(t). we improved our skills in MATLAB, and we learned some new functions and codes.