Why does gsm interfere

Effects of Interference. Sources of Interference. Types of Interference. By keeping the frequency separation between each channel in a given cell as large as possible, the adjacent interference may be reduced considerably.

Google serves cookies to analyze traffic to this site and for serving personalized ads. Learn more. Skip to content. Last updated: 17th Jun ' But now we have a situation where there are so many devices radiating either at the same time or in rapid succession that it starts to be noticeable to other devices.

That situation is poised to get worse. At present, the principal operating frequencies of 4G cell cphones are in the range of MHz to MHz. Next year, the Federal Communications Commission is scheduled to start auctioning off spectrum around MHz. If cell phones move into the newly available lower frequencies, they will start to overlap with a much larger portion of the cable TV frequency range.

It was an AM signal, and they determined a test method suited to the analog cell phone standards of the day and the few wireless devices that there were. The devices experiencing interference today are much more complicated. In the early stages of the standard, they were concerned with interfering with hearing aids, RS communication, and analog television.

Now we have high-speed communication systems and digital television. And the characteristics of these signals are beginning to look more and more like LTE signals. The PML team conducted its tests at several frequencies between MHz and MHz that represent a sample of current and future frequencies at which cable systems and cell phones must coexist.

The power cable can act as an antenna. In analogue times, this sometimes resulted in hearing the actual audio content of radio chatter, often on public PA systems, which were sensitive to stray radio frequency emissions. To answer this question — or ask a new one — email lastword newscientist. Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

Particularly the frequency range around MHz shows a very low interference threshold. Based on the interference levels found with CW signals, which are below the mobile phone emissions, we recommend similar precautions as for patients with cardiac pacemakers: 1. The phone should be used at the ear at the opposite side of the implant and 2. The patient should avoid carrying the phone close to the implant.

Today, the use of mobile phones is widespread and the number of users is increasing rapidly. It is generally known that an electromagnetic field of adequate intensity and frequency may interfere with implanted devices. Mobile phones are regarded as a potential source of electromagnetic interference with pacemakers [ 1 ]-[ 18 ] and defibrillators [ 6 , 19 , 20 ].

An extensive review of the literature [ 21 , 22 ] demonstrated that up to now no examinations on electromagnetic compatibility aspects of deep brain stimulators DBS and mobile phones have been published.

The malfunctions inhibition, switch to the safety modus, i. These malfunctions depend on various parameters: frequency, transmitting power, modulation principle of the mobile phone system, distance between mobile phone and pacemaker, implantation depth, operating mode of the pacemaker as well as the interference immunity of the pacemaker. For older pacemakers a safety distance of 6 inches 15 centimeters is sufficient to avoid malfunctions, although some publications recommend less than 6 inches.

The use of the mobile phone on the opposite side of the pacemaker's location reduces the probability of interference. Subsequently, pacemaker patients should not carry the mobile phone in the breast pocket close to the pacemaker or, if the pacemaker is located in the abdomen, not on a belt, when it is switched on.

Defibrillators seem to be less sensitive than pacemakers regarding electromagnetic fields emitted by mobile phones. Generally, the same precautions 6 inches or 15 centimeter minimum distance as in the case of pacemakers should be encouraged. If these precautions are adhered to the possibility of interference with defibrillators can be minimized.

The increasing use of neurostimulators and mobile phones, and the lack of information on possible disturbance of DBSs due to exposure from mobile phones motivated us to carry out this study. Unlike pacemakers and defibrillators, DBSs have no sensing inputs and therefore they should be more robust regarding electromagnetic interference. However, stimulation leads could act as antenna, picking up radio frequency RF currents and leading them into the device. Feed through filters should be able to handle this problem.

However, the manufacturer did not disclose information of the implant design, the electronic circuit design, whether feed though filters where used or not and which other electromagnetic compatibility precautions were taken. Neurological pulse generators are used as DBSs in the treatment of Parkinson's disease or as spinal cord stimulators. Located in the chest region under the skin, the DBS stimulates certain areas of the brain, namely the thalamus or subthalamus [ 23 , 24 ].

A programming device can telemetrically adjust the stimulation parameters such as frequency, amplitude, and pulse duration. Two critical locations of the phone in respect of interference that correspond to typical use scenarios can be found: The region around the ear due to the closeness of the mobile phone antenna to the leads of the DBS and the breast region due to the potential closeness of the mobile phone to the DBS. The experiments were carried out on two implants of the same type, with standard electrodes Medtronic Type and leads with a length of 51 centimeter cm.

One implant had already been used in a patient and therefore it showed a low battery capacity. Unipolar stimulation was used between the positively charged implant case and the negatively charged electrode tip pole 0. This stimulation was chosen because interference tests with pacemakers and defibrillators have uncovered unipolar stimulation to be more sensitive than bipolar stimulation [ 10 , 12 , 20 ]. Electromagnetic interference occurs often when electronic devices are brought to their functional limits.

Knowing that some stimulation settings are not usual stimulation parameters, we selected these stimulation settings to operate the implant at its functional limits provoking possible interference. Table 1 shows all stimulation parameter settings.

The phantom consists of three parts: the skull, the trunk, and the skull-trunk connection as shown in Figure 1. The skull and trunk are filled with liquid phantom materials simulating brain tissue and muscle tissue. The skull-trunk connection establishes the electrical connection between the two liquid phantom materials and avoids mixing them. The skull-trunk connection consists of a tube with an inside diameter of 4.

The implant and the leads are placed 1 cm below the inner surface of the phantom shell. This results in a 1 cm thick layer of phantom liquid between the inner surface of the 3 mm thick phantom shell and the surface of the implant. Figure 2 shows the implant holder and the lead holder. The electrode goes 3. Figure 3 shows the electrode and the electrode holder in the phantom skull. Reflections and the influence of external interference sources were minimized using a shielded anechoic chamber for all experiments see Figure 4.

Implant and Lead Holders. Common phantom liquids can only be produced for a single frequency or a limited frequency range. Because permittivity and conductivity are functions of frequency, it was necessary to develop two phantom materials.

The liquid phantom materials used in this experiment were mixed for MHz and MHz. The composition of the phantom materials is listed in Table 2. The dielectric properties of human tissue were taken from [ 25 ]. The respective properties of the phantom liquids and the jelly phantom material were measured with the "Dielectric Probe Measurement System" HPM from Hewlett Packard.

All dielectric properties can be found in Table 3. In order to determine the influence of the plastic phantom shell on the field distribution, the difference in the attenuation between two dipoles with and without phantom shell were measured.

The network analyzer HP D was used for measuring the attenuation.