Abstract: On a radio frequency signal path a transmission phase shifter causes a phase shift. From a first end of said phase shifter comes a first sample, and from a second end of said phase shifter comes a second sample. Another phase shifter changes the phase of the second sample by the same magnitude as said transmission phase shifter. A measurement circuit combines the phase-shifted second sample with a phase-inverted version of the first sample to produce an output indicative of a power level of the original signal on the radio frequency signal path.

Abstract: A method and an arrangement for transmitting and receiving RF signals, associated with different radio interfaces of communication systems, employ a direct conversion based transceiver which substantially comprises one receive signal branch and one transmit signal branch. Mixing frequencies of the different systems are generated by a single common synthesizer by use of an output frequency divider in combination with the synthesizer, and by use of filtering corresponding to a system channel bandwidth by means of a controllable low-pass filter operating at baseband frequency.

Abstract: The invention relates to optimizing the efficiency of a power amplifier of a transmitter. The objectives of the invention are achieved with a solution in which a voltage level of an output signal of an amplifier stage (301, 302) is detected (305, 306) at a signal output of each amplifier stage and the detected information is used for controlling a supply voltage of each amplifier stage in a way so that the unnecessarily high levels of the supply voltages can be avoided thus improving efficiency of the power amplifier.

Abstract: A frequency-mixing device performing voltage multiplying and low-pass filtering operations in addition to frequency mixing is provided. The three operations may be carried out with the same components by designing the frequency mixer appropriately. The frequency mixer comprises a first capacitance connected in series to the input of the frequency-mixing device, a first switch connected in parallel to the first capacitance, a second switch connected in series to the first capacitance, and a second capacitance connected in parallel to the second switching means. The switches are controlled by a local oscillator signal to close and open alternately according to a change in the voltage level of the first oscillator signal.

Abstract: A frequency-mixing device performing voltage multiplying and low-pass filtering operations in addition to the frequency mixing is provided. The three operations may be carried out with the same components by designing the frequency mixer appropriately. The frequency mixer comprises a balanced input port to receive a balanced input signal, an oscillator signal input port to receive a first and a second oscillator signal and a first, a second, and a third capacitance. First switching means are arranged to connect, in response to the first oscillator signal, the first and the second capacitance between a first and a second input port of the balanced input port. Second switching means are arranged to connect, in response to the second oscillator signal, the first capacitance between the first input port and the third capacitance and the second capacitance between the second input port and the third capacitance. An output port is connected to terminals of the third capacitance.

Abstract: A passive amplifier structure capable of multiplying the voltage of an input signal is provided. In a first stage, a first and a second capacitance are connected between a first and a second input port of a balanced input port in response to a first oscillator signal. In a second stage, in response to a second oscillator signal having a phase different from that of the first oscillator signal, the first capacitance is connected between the first input port and a third capacitance and the second capacitance is connected between the second input port and the third capacitance. An output voltage over the third capacitance is obtained from terminals of the third capacitance. Presented embodiments also describe an automatic gain control feature.

Abstract: A power amplifier integrated into an RF-IC (integrated circuit carrying radio frequency signals) comprises an active stage (350) and a passive stage (360), the passive stage being electrically coupled between the active stage and a load of the power amplifier. Electrically conductive elements (305) accomplishing an electrical connection between the active part and the passive part of an RF-IC are designed in a way that the electrically conductive elements perform at least part of impedance transformation on a signal path from signal output terminals of the active stage to signal output terminals of the passive stage.

Abstract: A circuit for rounding the edges of a digital pulse so as to reduce interference has a first rounding block, a second rounding block and an output stage. The first rounding block rounds the second and fourth pulse edges so as to prolong rising and falling time of the digital pulse. The second rounding block rounds the first and third pulse edges in accordance with non-linear characteristics of a semiconductor of the second rounding block. The output stage is a feedback circuit where the first rounding block is coupled with the second rounding block and the second rounding block is coupled with the feedback circuit.

Abstract: An electronic device 300 comprises a processing component 330 for reducing electromagnetic interferences. The processing component 330 is adapted to determine an activity status of at least one first component 311-315 operating in at least one known frequency range. The processing component 330 is further adapted to adjust an operating frequency of an active second component 321-322 depending on the determined activity status of the at least one first component 311-315. The invention relates equally to a chipset 330, to a method, to a software code 331 and to a software program product realizing the functions of the processing component 330.

Abstract: A method and arrangement for transmitting and receiving RF signals, associated with different radio interfaces of communication systems, employ a direct conversion based transceiver which substantially comprises one receive signal branch and one transmit signal branch. Mixing frequencies of the different systems are generated by a single common by use of an output frequency divider in combination with the synthesizer, and by use of filtering corresponding to a system channel bandwith by means of a controllable low-pass filter operating at baseband frequency.

Abstract: The invention relates to optimizing the efficiency of a power amplifier of a transmitter. The objectives of the invention are achieved with a solution in which a voltage level of an output signal of an amplifier stage (301, 302) is detected (305, 306) at a signal output of each amplifier stage and the detected information is used for controlling a supply voltage of each amplifier stage in a way so that the unnecessarily high levels of the supply voltages can be avoided thus improving efficiency of the power amplifier.

Abstract: A method and arrangement is shown for performing analog signal processing tasks like impedance matching, phase shifting, and/or signal filtering on a signal path from a signal source to a load so that a number of electrical components is smaller than that of solutions according to prior art for performing corresponding analog signal processing tasks. The signal source can be e.g. a power amplifier of a transmitter and the load can be e.g. an antenna of the transmitter. A solution is shown in which a same ninety degree phase shifter element (910) is used for performing more than one of the analog signal processing tasks of the kind mentioned above.

Abstract: A power amplifier integrated into an RF-IC (integrated circuit carrying radio frequency signals) comprises an active stage (350) and a passive stage (360), the passive stage being electrically coupled between the active stage and a load of the power amplifier. Electrically conductive elements (305) accomplishing an electrical connection between the active part and the passive part of an RF-IC are designed in a way that the electrically conductive elements perform at least part of impedance transformation on a signal path from signal output terminals of the active stage to signal output terminals of the passive stage.

Abstract: A signal carrying microstrip (510) is an integral part of the passive part (502) or the active part (501) of an RF-IC (integrated circuit carrying radio frequency signals). The ground plane (511) is an integral part of the base plate (503) of an RF-IC. The distance (h) between the microstrip (510) and the ground plane (511) is determined by the geometrical properties of the passive or the active part, of the base plate, and of the elements that act as spacers between the passive or active part and the base plate. The inventive microstrip structure allows the use of microstrips with different widths in an RF-IC without compromising the other important electrical characteristics like impedance level and inductive coupling. This opens the door for constructing a balun integrated into an RF-IC being able to e.g. make an impedance matching between different impedance levels.

Abstract: A measurement circuit for measuring a level of a radio frequency signal comprises a first signal path adapted to conduct a first version of a radio frequency signal and a second signal path adapted to conduct a second version of said radio frequency signal. The first and second versions have different phases. A combining circuit (301, 302, 405, 406, 407, 501, 502, 503, 605, 606, 607, 608, 609, 610, 801, 802) is coupled to receive the first version and the second version of the radio frequency signal. The combining circuit comprises a phase shifter part (301, 405, 406, 605, 606, 607, 801) adapted to change the phase of at least one of the first version and the second version of the radio frequency signal to make the phases of the first version and the second version equal, and an adder part (302, 407) adapted to produce a sum of the first version and the second version the phases of which were made equal, the sum being indicative of the level of the radio frequency signal.

Abstract: A method and arrangement for receiving a frequency modulated signal, includes mixing the frequency modulated signal into a low-frequency signal, detecting the falling and rising edges of said low-frequency signal and forming a second signal on the basis of the edge detection, where the frequency of the second signal is twice the frequency of the low-frequency signal, and frequency detecting the second signal to form a demodulated signal.

Abstract: A direct voltage component of a signal which has been received and converted to a baseband is separated by a first separator in a signal line. Also the direct voltage components of both the signal preceding the separator and the signal following the separator are controlled by control signals. Thus a baseband signal line preceding the first separator can be direct current coupled.

Abstract: The invention relates to a method and arrangement for receiving a frequency modulated signal, and especially for demodulating the signal. The invention is applicable especially in the receiver of a mobile station. One idea of the invention is to convert a radio frequency, frequency modulated signal directly into a low-frequency signal, and to perform the demodulation by forming by means of the falling and rising edges of said low-frequency signal a second signal, the frequency of which is twice the frequency of the low-frequency signal, and by frequency detecting said second signal. By means of the invention, the advantages of the direct conversion technique, such as low power consumption, are achieved in the reception of the frequency modulated signal,. The required components can be advantageously manufactured on an integrated circuit. Besides these advantages, a good quality of the detected signal is achieved.

Abstract: A linear power amplifier arrangement is used for providing a selectable amount of amplification to a radio frequency signal to be amplified. The arrangement comprises a first parallel amplifier branch and a second parallel amplifier branch and means for conducting the radio frequency signal to be amplified selectably to one of the parallel amplifier branches. Additionally it comprises in the first parallel amplifier branch a series connection of a predistorter and a nonlinear amplifier, where said predistorter is arranged to compensate for the nonlinearity of said nonlinear amplifier.

Abstract: The invention relates to a method and a circuit arrangement for reducing the offset voltage of a signal. The invention can be applied preferably in direct conversion receivers which are used, for example, in mobile stations used in digital time-division cellular systems. According to the invention, the direct voltage component of a signal is separated by a capacitor (C1) and the offset voltage is reduced by connecting a second signal (S2) to the output (P2) of the capacitor, the amplitude of this signal being determined on the basis of a first signal (S1) preceding the capacitor (C1). The second signal (S2) is formed preferably by high-pass filtering said first signal (S1) and by summing a reference voltage (Vref) to the high-pass filtered signal (S3). By using the solution according to the invention, it is possible to reduce the offset voltage also when there are no breaks in the received baseband signal.