Modulation is the process of adding information to a carrier signal. It consists of two parts: the message signal and the carrier signal. When the message signal is multiplied with the carrier signal, it results in a modulated signal. The message signal contains the input information that needs to be transmitted. It is passed through an input transducer to create the message signal. The carrier signal is a high frequency sinusoidal wave that carries the message signal. In the experiment, the students will set up a circuit to define the voltage on a voltmeter at frequencies of 4kHz and 1kHz by connecting wires between a power supply, voltmeter, and function generator.

1. Lab 1 :
((modulation))
Introduction:
Student's name I.D
Abdullah faisal aljabri 3200730
Shaker awad almaghathoi 3200700
Abdurahman ali alobaid 3200142
AbdulAziz saud alharbi 3200169
‫طيبة‬ ‫جامعة‬
‫الهندسة‬ ‫كلية‬
‫الكهربائية‬ ‫الهندسة‬
‫معمل‬‫نظرية‬‫االتصاالت‬
‫واالنظمة‬
Taibah University
Engineering
Department
Electrical Engineering
Communication Theory
and Systems

2. Modulation is the process of adding information to a steady waveform or to an
electronic or optical carrier signal, usually applied to electromagnetic signals.
Or Transforms a low frequency signal to a high frequency signal.
#theory:
The modulation consists two parts. First one is the massage signal.
second one is the carrier. When we multiple is the massage signal and the
carrier we get a modulated signal
*massage signal:
To create a massage signal It has to be passed in stages in the following:
1/input massage.
2/input transducer(create a massage signal). { m(t) }.
*carrier:
It is a sinusoidal high frequency signal neat and clean which carries the
modulating signal. C(t)= cos(2πfct)
*a modulated signal:
The baseband signal changes one of the parameters of the carrier and the
resulting high frequency signal.
figure 1: The block diagram of the modulation
S(t)=m(t)*cos(2πfct).
Steps:
1-run electrical panel of the two buttons (operating buttons).

3. 2 - Take a red wire entrances and first side put him in the entrance (5V / 3A)
with the red color, the second side in the entrance voltage (15+).
3- Take a blue wire entrances and first side put him in the entrance (5V / 3A)
with the blue color, the second side in the entrance ground (0+).
4- take another Red wire entrances and put him first side in the entrance (5V/
3A) with a red color, and the second side in the voltmeter with the red color.
5- take another blue wire entrances and put him first side in the entrance (5V/
3A) with a blue color, and the second side in the voltmeter with the blue color.
6- Keep voltmeter on the size Milli-volt ,and then from the electrical panel
define the voltage on 4 and 1 KHz frequency.
7- take Cable channel formed two branches black and red, then put it in the
telescope and put the black tip in the another ground in the electrical panel
and in the same place red tip at the entrance