what is cellphone jamming?

Question

what is the technology in it

Answer 1

It should be noted that cell jammers are not legal in the US.

Answer 2

A cell phone jammer is an instrument used to prevent cellular phones from receiving and transmitting the mobile signals to a base station. When used, the jammer effectively disables cellular phones in the area. These devices can be used in practically any location, but are found primarily in locales where a phone call would be particularly disruptive. These include churches, mosques, libraries, movie theaters, meeting rooms, and other places where silence is expected.

Jammers block cell phone use by sending out radio waves along the same frequencies that cellular phones use. This causes enough interference with the communication of cell phones and the towers to render the phones unusable. On most retail phones, the network would simply appear out of range. Most cell phones use different bands to send and receive communications from towers. Thus jammers can work by either disrupting phone to tower frequencies or tower to phone frequencies. Smaller handheld models block all bands from 800mhz to 1900mhz within a 30 foot range. Small devices tend to use the former method, while larger more expensive models may interfere directly with the tower. The radius of cell phone jammers can range from a dozen feet for pocket models to kilometers for more dedicated units. The TRJ-89 jammer can block cellular communications for a 5-mile (8 km) radius.

The main electronic components of a jammer are:
Voltage-controlled oscillator - Generates the radio signal that will interfere with the cell phone signal.
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 cell-phone network signal (part of the tuning circuit).
RF amplification (gain stage) - Boosts the power of the radio frequency output to high enough levels to jam a signal.

Answer 3

it means blocking the cell phone signals or scrambling it from entering a certain place where privacy is required.