It is the technical plan and content of equipment of cell phone jammer

Various mobile phones will recover sending and receiving the signal after 5-10s cell phone jammer turns off.
Passed an extension of the signal spectrum, given the capacity of the CDMA multiple access. Therefore, the understanding of the spread spectrum signal generation and its performance is very important. 2) spread spectrum modulation techniques must meet two basic requirements: A. pass the signal bandwidth must be much larger than the bandwidth of information. B. RF signal bandwidth information has nothing to do. 3) transfer the signal bandwidth Bt and information bandwidth Bi than called spread spectrum systems, processing gain G p, G p = Bt / Bi receiver using the same spreading code and the received signal correlation operation to recover the carrying the original information. 4) CDMA features: spread spectrum signal extends the spectrum of the signal, so it has a series of performance different from the narrowband signal: multi-site capabilities: anti-multipath interference; privacy performance; the ability of anti-human disturbance; with low the previously approved the performance of probability. It is the technical plan and content of equipment of cell phone jammer .
With suppression of narrowband interference. 5) CDMA in accordance with the use of spread spectrum modulation, can be divided into direct-sequence spread spectrum (DS), frequency hopping spread spectrum (FH), time-hopping spread spectrum (TH) and the composite spread-spectrum modulation as shown below : the DS FH TH composite CDMA, the DS / FH the TDMA MC-the CDMA the DS / TH the CDMA the MT-the CDMA FH / TH the DS / FH / TH, the CDMA pure CDMA broadband narrowband fast hopping slow frequency hopping (3) CDMA application of code division multiplexing The technology is mainly used for wireless communication systems, especially mobile communication systems. It not only can improve voice quality and reliability of data transmission and to reduce the impact of interference on the communications, but also increases the communication capacity of the system. Notebook computers, personal digital assistants (PDAs, Personal Date Assistant) Pocket PC (HPC, Handed Personal Computer) and other mobile computer networking and communications on a lot of use of this technology. Shielding frequency of  cell phone jammer  can be designed as follows.
In addition, the ITU also proposed a wideband code division multiple access WCDMA. The development of third generation mobile communication course (1) technological history in 1985, put forward the concept of the future public land mobile communication systems (FPLMTS). In 1994, the ITU-T and ITU-R officially together to FPLMTS. Subsequently into the IMT-2000 radio interface technology program solicitation formulation stage. In May 2000, the ITU formally approved technical standards for IMT-2000 radio interface, including WCDMA, CDMA, 2000, of TD-SCDMA standard. In the meantime, the major telecommunications companies are stepping up the third generation mobile communication system development. The necessary shielding frequency of  cell phone jammer  can be gained by such technologies.
In October 2001, October, NTT DoCoMo has finally launched the first 3G services of FOMA ", but reflects the capacity of the third generation of dynamic images and data services has not been opened, did not achieve the desired results, a loss. Many other companies have launched the third generation mobile communication systems in commercial use. (2) Technical Introduction to the history of wireless communications is the history of the frequency use efficiency, the history of mobile communications frequency use efficiency and user "displacement" expanded history. The third-generation mobile communications (3G, of The 3rd Generation, Mobile Communication) is actually a new communications technology. The necessary shielding frequency of  cell phone jammer  can be got by and filtration.