Method for controlling the power gain for outputting a transmitted signal from a radio device. At the beginning of the transmitted signal, the output power is increased to a preset power level along a preset characteristic curve. At the end of the transmitted signal, the preset power is decreased along the preset characteristic curve. The power gain is controlled accordingly by a control signal (8, 9). A reference control signal (5) is used for the rising and falling edges of the control signal (8, 9). The control signal (8, 9) is limited to a preset maximum control signal value (6, 7).

In a receiver for signals set in time slots within fixed length time frames, noise is supplied as an input signal and the received signal value is stored with measured temperature values. Temperature corrections for temperature are determined and stored to be applied subsequently.

An artificial ramping waveform profile is applied to a burst transmission power amplifier in order to reduce transients. A profile source is supplied with a plurality of pre-determined artificial ramping profiles. At the beginning of the burst transmission ramping period, one of the artificial ramping profiles is selected and fed to the power amplifier. The selection of the artificial ramping profile is based at least in part on the first message symbol of the message to be burst transmitted. Preferably, each different possible first message symbol has its own unique corresponding artificial ramping profile, and the corresponding waveform is used to artificially ramp the power amplifier when that message symbol is the first message symbol. At the end of the ramping period, the inputs to the power amplifier are switched to the traditional signal source, such as the FIR filters, etc., for receipt of the message symbols. The transmitted signal is based then on the response of the power amplifier to the artificial ramping profile and the message symbols. The generation of transient adjacent channel power is significantly reduced by artificially ramping the power amplifier rather than allowing for natural ramping. By choosing the artificial ramping profile based on the first message symbol, the phase trajectory changes near the end of the ramping period may be significantly smoothed, thereby lessening the generation of undesired harmonic power levels.

Transmitter architectures for a communications system having improved performance over conventional transmitter architectures. The improvements include a combination of the following: faster response time for the control signals, improved linearity, reduced interference, reduced power consumption, lower circuit complexity, and lower costs. For a cellular application, these improvements can lead to increased system capacity, smaller telephone size, increased talk and standby times, and greater acceptance of the product. Circuitry is provided to speed up the response time of a control signal. The control loop for various elements in the transmit signal path are integrated. A gain control mechanism allows for accurate adjustment of the output transmit power level. Control mechanisms are provided to power down the power amplifier, or the entire transmit signal path, when not needed. The gains of the various elements in the transmit signal path are controlled to reduce transients in the output transmit power, and to also ensure that transients are downward.

A system for controlling a magnetic field strength includes a magnetic field generator for generating a magnetic field for receipt by a responsive device and a controller in communication with the magnetic field generator for determining a strength of the magnetic field to a level sufficient for use in controlling the responsive device.