Wednesday, February 15, 2012

The daily maintenance is applied to cell phone blocker

Walsh code orthogonal property of the fully synchronized conditions, two of the same walsh code related value of 1, different walsh code mutual correlation value is 0 synchronization conditions walsh code is not being characteristics of cross. Therefore, we get a general in the sectors above 3 L is relatively large, and S (t) 1b, S-(t) 2b, S-(t) 1c, of S (t) 2c and other sectors of the signal relative call the signal came, so the red part of the above equation can be approximated to 0, the cell phone users 1a can easily demodulate the user PNi sector call signal on where the blue part of S (t) 1a. It will be better if the daily maintenance is applied to  cell phone blocker .
In practice, more than the red part is not 0, which is equivalent to the interference, this part of the interference is generated by the system, that is, since the interference part. These disturbances are from other sectors, we can see that with the increase of the increase of the pilot signal and the call user, interference will be a corresponding increase in signal with the user calls. If the user at the same time receiving a call to several signal is quite pilot signal, that is, pilot pollution exists, then on the style in the red part can not be ignored, will cell phone demodulation useful signal to produce extremely disruptive, and sometimes dropped calls because of the demodulator does not come out.  cell phone jammer can have different shielding range according to customer’s requirements.
When we calculate the green part during the walsh orthogonal autocorrelation is 0, indicating that in the same sector, regardless of how many users can demodulate the signal channel, the signal of other users of this signal with the same sector nothing to do. Zero means that the interference of the same sector. However, due to signal propagation in space will produce multipath walsh the autocorrelation characteristic time absolute synchronization, the presence of multipath damage walsh orthogonal properties of the green part of the calculation is not 0, that is the same a sector interference. RAKE receiver CDMA cell phone built-in three-way digital demodulation unit and a search unit, three-way digital demodulation unit can decode three different pilot signal can decode the different multipath signals in the same pilot. The cheating through using modern communication tool can be stopped and prevented in the examination room with help of cell phone jammer .
When the location of the cell phone had made more than three larger than T_ADD pilot, the fourth pilot, compared with the first pilot pollution sources, which produce the pilot pollution phenomena. Occur pilot pollution phenomenon, redundant pilot signal on the cell phone to use the guide frequency signal, not only do no good, but is a source of interference, an increase of the background noise of the system, cause the system to the frame error rate rise, affecting system various functions, and even lead to dropped calls. With the increase of the base station, the cell phone of the same place the guide frequency signal is increased, in particular, was a ring distribution of multiple base stations or base station when the height difference between the larger geographical, cross-district coverage signals a serious, resulting in a location to receive the strong pilot signal more easy to form a pilot pollution phenomenon. Detector of cell phone jammer intelligent system has the (green) indication light which means the working system operates normally.
Pilot pollution causes and solutions. Pilot pollution caused mainly due to the mutual interference between the signals between the multiple sectors. As the complexity of the wireless environment: topography, building distribution, street distribution, waters, and all aspects of the impact of the signal is very difficult to control, can not achieve the desired condition. Pilot pollution occurs mainly in the base station dense urban environment, because the base station of the city is dense, prone to several sectors of the pilot signal to cover the same area, while the indoor signal will leak to the outdoors as well as signal by the high-rise city Building of refraction reflection, it tends to cause pilot pollution. And then restart the detector of cell phone jammer intelligent system and software.

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