Abstract: The present invention relates to a filter correction unit (203a) as well as an RF filter including the correction unit for use in radio frequency transmission lines including a band pass filter (201) having input and output interfaces mounted in the signal transmission line. The filter (201) is chosen so as to transmit signals within a predetermined frequency range, the quality factor of the filter having predetermined limitations generating a known distortion to the signal. The correction unit (203a) has a first bus connected to said transmission line and to said filter, wherein the correction unit comprises at least one surface acoustic wave (SAW) transducer (204a-n), each transducer having two electrodes on a piezoelectric substrate where a first electrode is connected to said first bus and the other electrode connected to a second bus, the SAW transducer being adapted to distort a transmitted signal with a factor being the inverse of said known distortion of the filter (201).

Abstract: The present invention relates to a filter correction unit (203a) as well as an RF filter including the correction unit for use in radio frequency transmission lines including a band pass filter (201) having input and output interfaces mounted in the signal transmission line. The filter (201) is chosen so as to transmit signals within a predetermined frequency range, the quality factor of the filter having predetermined limitations generating a known distortion to the signal. The correction unit (203a) has a first bus connected to said transmission line and to said filter, wherein the correction unit comprises at least one surface acoustic wave (SAW) transducer (204a-n), each transducer having two electrodes on a piezoelectric substrate where a first electrode is connected to said first bus and the other electrode connected to a second bus, the SAW transducer being adapted to distort a transmitted signal with a factor being the inverse of said known distortion of the filter (201).

Abstract: There is provided an analog phase locked oscillator comprising a sampling phase detector, a loop filter, a voltage controlled oscillator, a frequency multiplier and a feedback loop where the feedback loop connects the output of said oscillator with the input of said phase detector through said frequency multiplier. The sampling phase detector is adapted to perform a discrete phase comparison between a reference frequency and the multiplied feedback signal. The voltage controlled oscillator is adapted to give out a constant frequency at a multiply of the reference frequency divided with the multiplication factor of the multiplier.

Abstract: A radio filter has a band pass filter for passing a desired band of signal frequencies and a band stop filter for reducing the passing of a band of undesired signal frequencies. The filter comprises an input terminal, an output terminal, and a filter having a multiple of transmission lines arranged between said input and output terminal which filters input signals through said input terminal to pass signals of a given frequency band. A ground is connected to said transmission lines at first ends of said multiple of transmission lines and acoustic impedance elements are connected between said ground layer and second ends of said multiple transmission lines for providing a stop band filter function of the input signals, and whereby the input signal after band pass filtering and stop band filtering is provided at said output terminal.

Abstract: There is provided an analog phase locked oscillator comprising a sampling phase detector, a loop filter, a voltage controlled oscillator, a frequency multiplier and a feedback loop where the feedback loop connects the output of said oscillator with the input of said phase detector through said frequency multiplier. The sampling phase detector is adapted to perform a discrete phase comparison between a reference frequency and the multiplied feedback signal. The voltage controlled oscillator is adapted to give out a constant frequency at a multiply of the reference frequency divided with the multiplication factor of the multiplier.

Abstract: A radio filter has a band pass filter for passing a desired band of signal frequencies and a band stop filter for reducing the passing of a band of undesired signal frequencies. The filter comprises an input terminal, an output terminal, and a filter having a multiple of transmission lines arranged between said input and output terminal which filters input signals through said input terminal to pass signals of a given frequency band. A ground is connected to said transmission lines at first ends of said multiple of transmission lines and acoustic impedance elements are connected between said ground layer and second ends of said multiple transmission lines for providing a stop band filter function of the input signals, and whereby the input signal after band pass filtering and stop band filtering is provided at said output terminal.

Abstract: A surface acoustic wave transducer with a piezoelectric substrate and at least two electrodes on the surface of the substrate wherein the electrodes comprise fingers which overlap with the fingers of another electrode in a projection parallel to the surface of the substrate is described. The fingers comprise coupling fingers which are located adjacent to a finger of another electrode and which have a high coupling efficiency to the surface acoustic waves. A structure with low surface acoustic wave reflection is located between at least two coupling fingers of the same electrode and the surface acoustic wave propagation velocity of the low reflecting structure and the coupling fingers is equal. Furthermore, a filter comprising the transducer is proposed.