Abstract: Various signal processing techniques may benefit from appropriate handling. For example, certain signal processors may benefit from quarter wavelength unit delay and complex weight coefficient continuous-time filters. A method can include splitting an input signal into a plurality of signal paths. The method can also include complex weighting, for each signal path, a respective signal. The method can further include summing outputs of the signal paths. The method can additionally include providing an output comprising the sum of the signal paths. The complex weighting can be configured to independently control gain, phase and delay of the output signal over broadband.

Abstract: Appropriate signal processing may be beneficial in a variety of communication systems and elements thereof. For example, time domain digital pre-distortion may benefit from suitable treatment of frequency switching. A method can include determining whether an instantaneous frequency of an input signal is positive or negative. The method can also include selecting a pre-distortion model from a set of pre-distortion models based on the determination of positive or negative instantaneous frequency. The method can further include applying the selected pre-distortion model to the input signal for a time corresponding to the determination of instantaneous frequency to provide an output signal. The method can additionally include providing the output signal to a power amplifier.

Abstract: Appropriate signal processing may be beneficial in a variety of communication systems and elements thereof For example, time domain digital pre-distortion may benefit from suitable treatment of frequency switching. A method can include determining whether an instantaneous frequency of an input signal is positive or negative. The method can also include selecting a pre-distortion model from a set of pre-distortion models based on the determination of positive or negative instantaneous frequency. The method can further include applying the selected pre-distortion model to the input signal for a time corresponding to the determination of instantaneous frequency to provide an output signal. The method can additionally include providing the output signal to a power amplifier.

Abstract: Various signal processing techniques may benefit from appropriate handling. For example, certain signal processors may benefit from quarter wavelength unit delay and complex weight coefficient continuous-time filters. A method can include splitting an input signal into a plurality of signal paths. The method can also include complex weighting, for each signal path, a respective signal. The method can further include summing outputs of the signal paths. The method can additionally include providing an output comprising the sum of the signal paths. The complex weighting can be configured to independently control gain, phase and delay of the output signal over broadband.

Abstract: The solution controls electric operational power to be fed to an amplifier. The control can be carried out, for instance, in accordance with a predetermined signal. The operational power is fed to the amplifier with a voltage source unit and a current source unit, and the operational voltage that the voltage source unit feeds to the amplifier is controlled. The current source unit feeds at least some of the operational electric current of the amplifier.

Abstract: The solution controls electric operational power to be fed to an amplifier. The control can be carried out, for instance, in accordance with a predetermined signal. The operational power is fed to the amplifier with a voltage source unit and a current source unit, and the operational voltage that the voltage source unit feeds to the amplifier is controlled. The current source unit feeds at least some of the operational electric current of the amplifier.

Abstract: An electronic circuit for adjusting a property of an input signal of a non-linear element is disclosed. A detector detects a strength of the input signal. An analog controller forms a control signal as a piecewise approximation of a non-linear dependency between the property and the strength of the input signal detected by the detector. An adjusting circuit adjusts the property of the input signal according to the control signal from a controller.

Abstract: An amplitude controller for adjusting the amplitude of a radio-frequency signal, the amplitude controller includes elements for splitting (302A) an amplitude adjustment input signal into one or more signal pairs, each signal pair having two partial signals, elements for generating (302B) an inverse-phase-sized phase difference between the partial signals of each signal pair, elements for adjusting (302C, 302D, 302F) the amplitudes of the partial signals of each signal pair by employing the mutual magnitude of the amplitudes of the partial signals as the factor controlling the adjustment, and elements for summing up (302E) the partial inverse-phased and amplitude-adjusted signals as an output signal.

Abstract: An adjusting circuit for adjusting an amplitude of a radio frequency signal is disclosed. The adjusting circuit includes a plurality of terminals for input and output, a matching component having an effect on matching a signal input and a signal output to and from the terminals. The adjusting circuit also includes at least one adjustable resistance unit between the matching component and ground for changing a resistance of the input and the output of at least one terminal of the amplitude adjusting circuit. The adjusting circuit for adjusting an amplitude of a signal also may include a plurality of terminals for input and output, at least one pair of adjustable impedance units. Each pair of the adjustable impedance units is placed between a pair of input and output terminals. Each of the adjustable impedance units is coupled in parallel between a signal line and ground, and the impedance units of each pair have complementary reactances with respect to each other.

Abstract: An electronic circuit for adjusting a property of an input signal of a non-linear element is disclosed. A detector detects a strength of the input signal. An analog controller forms a control signal as a piecewise approximation of a non-linear dependency between the property and the strength of the input signal detected by the detector. An adjusting circuit adjusts the property of the input signal according to the control signal from a controller.

Abstract: The present invention relates to a summing network comprising: a summing point (P) having interfaces for coupling summing network branches to the summing point, and an interface for coupling the summing point (P) to an antenna (ANT), and channel units (TX1 to TX3) arranged in the branches, and channel unit-specific band-pass filters (1 to 3), whose pass frequencies correspond to the frequency or frequencies of the corresponding channel unit. To facilitate tuning the summing network, a compensation element (7) is coupled to the summing network between the summing point (P) and the antenna (ANT), the load effect of said compensation element corresponding substantially to the load caused to the summing point (P) by the branches coupled to the summing point.

Abstract: The present invention relates to a summing network comprising: a summing point (P) having interfaces for coupling summing network branches to the summing point, and an interface for coupling the summing point (P) to an antenna (ANT), and channel units (TX1 to TX3) arranged in the branches, and channel unit-specific band-pass filters (1 to 3), whose pass frequencies correspond to the frequency or frequencies of the corresponding channel unit. To facilitate tuning the summing network, a compensation element (7) is coupled to the summing network between the summing point (P) and the antenna (ANT), the load effect of said compensation element corresponding substantially to the load caused to the summing point (P) by the branches coupled to the summing point.

Abstract: The present invention provides a method and apparatus for auto-biasing an amplifier. The invention is particularly useful in biasing non-linear amplifiers and amplifiers whose input signal may be amplitude modulated (AM). The auto-bias system of the present invention has an active bias feedback loop that continuously adjusts the bias condition of an amplifier to a wanted state during amplifier operation by monitoring a physical quantity indicative of the operating state of the amplifier and controlling the amplifier bias so as to control the amplifier operating point sufficiently to compensate for variations in amplifier electrical characteristics, amplifier load, amplifier temperature, and input signals. In the case of an AM input signal, the auto-bias system of the present invention may provide sample and hold function so that the amplifier bias is the same during high power periods and low power periods, even though during high power periods the amplifier may be operating in a non-linear region.

Abstract: A device and a method for adjusting a bandpass filter, especially a combiner filter. The method includes deriving an RF sample signal proportional to the power of a modulated RF signal which is one of: passing forward to the bandpass filter, reflected from the input of the bandpass filter and passed through the bandpass filter; down-converting the sample signal by another RF signal; detecting the signal strength of the mixing result; adjusting the center frequency of the passband of the bandpass filter on the basis of the detected signal strength. There is an essential frequency or modulation difference between the signals to be mixed, and so the mixing result is an AC signal of a lower frequency. No accurate adjustment of the phase relation of the signals to be mixed is required. Preferably, the frequency or phase difference between the signals to be mixed is accomplished by utilizing the phase modulation contained in the transmission when one of the signals is unmodulated.

Abstract: Tuning a combiner filter, which includes two separate tuning modes: coarse adjustment applied when the combiner is taken into use by utilizing a measuring branch for forward power and a coarse measuring branch for reflected power; and fine adjustment applied in continuous operation by utilizing the measuring branch for forward power and a fine measuring branch for reflected power. The two-stage adjustment decreases the mutual interference of the filters during tuning. The correct tuning frequency of the combiner filter is obtained as the average point of the reversing points obtained in the adjustment process, the filter being driven to the average position. This so-called positional average tuning has two advantages: the effect of noise present in the power measuring line is reduced, and the tuning error caused by the termination of the dynamics of the A/D converter positioned after the detector at low power levels and good combiner filter settings is diminished.

Abstract: A device for tuning a combiner filter. The measuring signals (P.sub.rl . . . P.sub.rn, P.sub.F1 . . . P.sub.Fn) of a number of different combiner filters are multiplexed to the same detectors. Multiplexing allows the measuring and adjusting electronics required by the tuning and adjusting means of combiner filters to be simplified considerably especially with a high number of combiner filters. Multiplexing of measuring signals is used primarily to select the sample signals of the forward and reflected power of one and the same combiner filter to be tuned for the measuring electronics. In the invention selectors for reflected power and forward power are independent of each other, which allows isolation measurement between different channels. The sample signal of the forward power of one combiner filter and the sample signal of the reflected power of another combiner filter are thus connected to the measuring electronics.