A mobile phone jammer is an instrument used to prevent cellular phones from receiving signals from base stations. When used, the jammer effectively disables cellular phones. These devices can be used in practically any location, but are found primarily in places where a phone call would be particularly disruptive because silence is expected.

1. Topic:
Mobile Signal jammer

2. Group: 05
Group Members:
Name AIUB ID
Rahman Md. Jubayer 12-20824-1
Puspita Shaha 12-20840-1
Hossain Bayezid 12-20427-1
Rahman Afroza 12-20371-1
Sazid Hosni Mubarak 12-20426-1
Faculty: RETHWAN FAIZ

3. Content:
 Mobile Signal Jammer
 Type of Jammer
 How Jammer Works
 Block Diagram
 Circuit Design
 Legality
 Application
 Conclusion
 Reference

4. Mobile Signal jammer:
A mobile phone jammer is an instrument used to prevent cellular phones from receiving
signals from base stations. When used, the jammer effectively disables cellular phones.
These devices can be used in practically any location, but are found primarily in places
where a phone call would be particularly disruptive because silence is expected.
Type of jammer:
There are two type of cell phone jammer.
 GSM Jammer
 CDMA jammer

5. Jamming devices overpower the cell phone by transmitting a signal on the same frequency as
the cell phone and at a high enough power that the two signals collide and cancel each other
out.To jam a cell phone, all you need is a device that broadcasts on the correct frequencies.
How jammer works:

6. Disrupting the communication between the phone and the cell-phone base station in the
town. It's a called a denial-of-service attack. Although different cellular systems process
signals differently, all cell-phone networks use radio signals that can be interrupted. GSM,
used in digital cellular and PCS-based systems, operates in the 900-MHz and 1800-MHz
bands inAsia.

7. Block Diagram:
Power
Supply
Oscillator
Noise
Generator
Amplifier Antenna
Antenna:
Every jamming device has an antenna to send the signal. Antennas are external to provide longer range
and may be tuned for individual frequencies.
Circuitry:
Tuning circuit - Controls the frequency at which the jammer broadcasts its signal by sending a particular
voltage to the oscillator
Noise generator - Produces random electronic output in a specified frequency range to jam the signal
RF amplification (gain stage) - Boosts the power of the radio frequency output to high enough levels to
jam a signal
Power supply:
Smaller jamming devices are battery operated. Some look like cell phone and use cell-phone batteries.
Stronger devices can be plugged into a standard outlet or wired into a vehicle's electrical system.

8. circuit design:

9. BD Mobile Frequency Info:
Robi:
Robi uses GSM 900 MHz standard and operates on allocated 12.8 MHz frequency
spectrum.
GrameenPhone:
GrameenPhone uses GSM 900/1800/2100 MHz standard and operates on allocated
2×7.4/2×7.2 + 2×7.4 MHz frequency spectrum.
Banglalink:
Banglalink uses GSM 900 MHz standard and operates.
Airtal:
Airtal uses GSM 900/2100 MHz standard and operates.

10. Application:
 To maintain the complete silence in library and lecture hall
 To avoid fraud in examination hall
 For providing security in business conference, seminar, meeting
 Police and defense can use for their security purpose
 Personal safety reason
Legality:
Mobile phone jammer illegal to use in maximum country. In Bangladesh its Illegal to
operate, supply or possess. It can be use only for the government purpose.

11. Conclusion:
Every technology has good aspect as well as bad aspect the important thing is, how
we are using it. Cell phone jammer are very useful to the society from the anti-social
elements. Cell phone jammer prevent students from carrying phone to the colleges.

12. Reference:
1. Blockyourid.org, [Online: 2013], [Cited: 20.10.2015], Available:
http://mail.blockyourid.com/~gbpprorg/mil/celljam/simple/index.html
2. Btrc.gov.bd, [Online: 19.10.2010], [Cited: 20.03.2015], Available:
http://www.btrc.gov.bd/cellular-mobile
3. Instructables.com, [Online: 2006], [Cited: 22.10.2015], Available:
http://www.instructables.com/id/How-To-Create-Your-Signal-Jammer/
4. Mepits.com, [Online: 2005], [Cited: 22.10.2015], Available:
https://www.mepits.com/tutorial/326/Latest-Technologies/Mobile-Phone-
Jammer-How-it-works?-Application-Sectors

13. Question ?

14. Thank You