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 bandwidth by means of a controllable low-pass filter operating at baseband frequency.

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 bandwidth by means of a controllable low-pass filter operating at baseband frequency.

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 bandwidth by means of a controllable low-pass filter operating at baseband frequency.

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 bandwidth by means of a controllable low-pass filter operating at baseband frequency.

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 bandwidth by means of a controllable low—pass filter operating at baseband frequency.

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 bandwidth by means of a controllable low-pass filter operating at baseband frequency.

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 bandwidth by means of a controllable low-pass filter operating at baseband frequency.

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: An apparatus configured to separate from a received radio frequency (RF) signal a first low-frequency signal and a second low-frequency signal having different phases, up-convert the first low-frequency signal and the second low-frequency signal into a first intermediate frequency signal and a second intermediate frequency signal, respectively, and amplify the first and the second intermediate-frequency signals.

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 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: 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 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 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 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 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: 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.