Nokia Mobile Phones Limited

Raimo Ikonen

Pekka S Lonka

Pekka Mikkola

A procedure is utilized for forming the transmission and reception frequencies required for the operation of a digital radio telephone based on time division multiplex access, in particular, in a radio telephone for the GSM system. According to the procedure, the mixer frequencies used in the transmitter and the receiver of the radio telephone are formed by a synthesizer and a basic oscillator commmon to both the receiver and transmitter. The clock frequency for the logic of the radio telephone and the RF reference frequency to the synthesizer are produced by dividing the output frequency of the common basic oscillator.

Procedure for forming frequencies of a digital radio telephone

This invention relates to a method by which transients can be eliminated in an apparatus comprising a current source and several functional blocks at least one of which produces transients in the operating voltage. According to the invention, a switch separates the current source and the transient-producing block from the other blocks during the time that transients are being produced and connects the current source to the other blocks and to an energy-storing buffer during the time that transients are not being produced.

Method for the elimination of transients from the operating voltage of

The present invention concerns a circuitry for widening the power control range of radio telephone. A radio frequency signal is amplified in a controllable power amplifier (1). According to the invention, after the amplifier a controllable switch (4) is connected, which, while in a first state, does not substantially attenuate the RF power emitted transmitted from the power amplifier (1). The first power control range of the transmitter is thus produced. When the switch (4) is in a second state, it directs part of the RF power transmitted from the power amplifier (1) to a resistive element (R1) and permits part of the RF power to be transmitted to the output (RFout) of the transmitter. A second power control range is produced in this manner.

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Pertteli, Finland

Raimo Ikonen