The technology of mobile telephone systems relevant for risk assessment

Mobile personal phones are now a mass market product, and considering that the general population is exposed to the electromagnetic fields around the telephone, it is of importance that the biological, medical and epidemiological community understands the basic technology. The most common access systems, FDMA, TDMA and CDMA, are reviewed with respect to the level and time variation of the power radiated from the antenna. The time variation has become of prime interest due to the biological effects noted from amplitude modulated radiations. The emphasis is on the low frequency variation of the high frequency power, and on the low frequency fields themselves.