Nokia Corporation

Nokia Mobile Phones Limited

Jukka Varis

Seppo Rosnell

Esko J&auml;rvinen

Switching mode power amplifiers using pulse width modulation (PWM) and pulse position modulation (PPM) for generating bandpass signals is disclosed. Fully digital implemented transmitter structures having QPSK inputs for phase and amplitude are described.

Switching mode power amplifier using PWM and PPM for bandpass signals

In a modulation system, in order to provide a two-level signal with a desired modulation which is suited to be amplified by a switching mode power amplifier, the modulation system may include a first constant envelope modulator modulating a signal according to a first control signal, a second constant envelope modulator modulating a signal according to a second control signal, and a combining portion combining the output signal of the first and said second constant envelope modulator to a single, two-level pulse-width-modulated signal. The information which is to be represented by the modulation of the single, two-level pulse-width-modulated signal is coded in the first and the second control signals. The invention relates equally to a corresponding method for generating a modulated signal.

Method and system for a generation of a two-level signal

The invention relates to a power control structure comprising a switching mode power amplifier for receiving an input signal, for amplifying the received input signal and for providing the amplified signal as output signal. In order to enable a power control over a large range while preserving the efficiency of the power amplifier, the structure further comprises a first control arrangement for controlling the power level of the output signal at least at higher desired power levels by adjusting a power supply provided to the switching mode power amplifier, and in addition a second control arrangement for controlling the power level of the output signal at least at lower desired power levels by adjusting the power of the input signal before it is provided to the switching mode power amplifier. The invention relates equally to a corresponding method.

Power control for a switching mode power amplifier

The course of an oscillating signal is controlled in mutually alternative first active component (,) and second active component (,), both of which can be set into active state by a certain first value of a control signal brought to the component and which are in inactive state with a certain second value of the control signal. The signal is directed to pass through the first active component (,) by setting it into active state by a control signal (,) brought to it. At the same time, the second active component (,) is prevented from affecting the course of the signal by setting a control signal brought to it to a second value (,).

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Halikko, Finland

Jukka Varis