Patents by Inventor Stefan Barkaro

Stefan Barkaro has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8588403
    Abstract: In a line driver/receiver circuit where the line driver is connected with its output terminals to a load for supplying a transmit signal thereto and where the receiver is connected with its input terminals to the load for simultaneously receiving a receive signal therefrom, the transmit signal on the input terminals of the receiver is canceled by connecting the output terminals of the line driver to the load via equal complex sense impedances of an impedance value that is much smaller than the impedance value of the load impedance to match the load impedance, connecting the input terminals of the receiver to the load via equal first resistors and to respective output terminal of the line driver via equal second resistors, and providing transconductance amplifiers to sense the voltage across the sense impedances and supply corresponding currents to respective input terminal of the line driver.
    Type: Grant
    Filed: July 28, 2010
    Date of Patent: November 19, 2013
    Assignee: Lantiq Deutschland GmbH
    Inventors: Stefan Barkaro, Torbjorn Randahl
  • Patent number: 7839993
    Abstract: In a line driver/receiver circuit where the line driver is connected with its output terminals to a load for supplying a transmit signal thereto and where the receiver is connected with its input terminals to the load for simultaneously receiving a receive signal therefrom, the transmit signal on the input terminals of the receiver is canceled by connecting the output terminals of the line driver to the load via equal complex sense impedances of an impedance value that is much smaller than the impedance value of the load impedance to match the load impedance, connecting the input terminals of the receiver to the load via equal first resistors and to respective output terminal of the line driver via equal second resistors, and providing transconductance amplifiers to sense the voltage across the sense impedances and supply corresponding currents to respective input terminal of the line driver.
    Type: Grant
    Filed: April 9, 2004
    Date of Patent: November 23, 2010
    Assignee: Lantiq Deutschland GmbH
    Inventors: Stefan Barkarö, Torbjörn Randahl
  • Publication number: 20100289523
    Abstract: In a line driver/receiver circuit where the line driver is connected with its output terminals to a load for supplying a transmit signal thereto and where the receiver is connected with its input terminals to the load for simultaneously receiving a receive signal therefrom, the transmit signal on the input terminals of the receiver is canceled by connecting the output terminals of the line driver to the load via equal complex sense impedances of an impedance value that is much smaller than the impedance value of the load impedance to match the load impedance, connecting the input terminals of the receiver to the load via equal first resistors and to respective output terminal of the line driver via equal second resistors, and providing transconductance amplifiers to sense the voltage across the sense impedances and supply corresponding currents to respective input terminal of the line driver.
    Type: Application
    Filed: July 28, 2010
    Publication date: November 18, 2010
    Inventors: STEFAN BARKARÖ, TORBJÖRN RANDAHL
  • Patent number: 7801296
    Abstract: at least one self oscillating loop circuit which oscillates with a switching frequency (fs), wherein the self oscillating loop circuit (18, 19, 20) comprises an output driver (19) which is switched with said switching frequency and a loop filter (20) which feeds back an amplified loop signal output by said driver (19) to an input of said self oscillating loop and a trimming circuit (21) for trimming the switching frequency (fs) of said self oscillating loop circuit.
    Type: Grant
    Filed: January 27, 2005
    Date of Patent: September 21, 2010
    Assignee: Infineon Technologies AG
    Inventors: Karl Stefan Barkarö, Bo Bokinge, Jörg Hauptmann, Karl-Mikael Johanson, Lars Karlsson, Torbjörn Ivar Randahl
  • Patent number: 7282992
    Abstract: A class D-amplifier which amplifies an input signal applied to an signal input of said amplifier (21) to generate an amplified signal output by an signal output (28a, 28b) of said amplifier comprising a comparator (23) which compares the applied input signal with a switch signal to generate a pulse width modulated signal; a driving unit (24) which amplifies the pulse width modulated signal to generate the amplified output signal; and a feedback circuit which generates the self oscillating switch signal for the comparator (23).
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: October 16, 2007
    Assignee: Infineon Technologies AG
    Inventors: Karl Stefan Barkaro, Bo Bokinge, Carl-Mikael Johansson, Lars Karlsson, Torbjorn Ivar Randahl, Andreas Wiesbauer
  • Publication number: 20050286710
    Abstract: Broadband xDSL transceiver for transmitting and receiving signals in a predetermined broadband frequency range (?F) via a signal line which has a complex line impedance (ZL), wherein the xDSL transceiver (1) comprises a line driver (3) for driving a transmission signal applied to a signal input (4a, 4b) of said line driver (3) via said signal line; a receiver (8) for evaluating a reception signal received via said signal line and applied to a signal input of said receiver (8); an echo canceling bridge (10) for canceling the transmission signal at the signal input (9a, 9b) of said receiver (8); a sense impedance (11) connected to the signal line; a feedback resistor network (15a, 15b) provided between the sense impedance (11) and the signal input (4a, 4b) of said line driver (3) performing a synthesized termination impedance (ZT) of the xDSL transceiver (1) as a product of the sense impedance and an impedance synthesis factor (G); wherein the sense impedance (11) is a complex impedance (ZS) so that the
    Type: Application
    Filed: June 29, 2005
    Publication date: December 29, 2005
    Applicant: Infineon Technologies AG
    Inventors: Stefan Barkaro, Torbjorn Randahl, Carl-Mikael Johansson, Lars Karlsson, Bo Bokinge
  • Publication number: 20050156664
    Abstract: Line driver arrangement comprising a class-D switching amplifier having a switching frequency for receiving an input transmit signal and outputting an amplified transmit signal and a transformer having a predetermined leakage inductance for receiving the amplified transmit signal and outputting a transform signal as an output transmit signal. The leakage inductance is predetermined for low-pass filtering of the amplified transmit signal. The line driver arrangement reduces the number of additional discrete inductances, capacitances and or resistor for forming low-pass filters significantly. The inventive line driver arrangement is particularly power-efficient due to the included class-D switching amplifier. The predetermined leakage inductance leads to a suppression of a resonance due to the switching frequency of the class-D amplifier in the power spectral density. Hence, the inventive line driver arrangement complies at least with the ADSL PSD mask requirements.
    Type: Application
    Filed: January 20, 2004
    Publication date: July 21, 2005
    Inventors: Torbjorn Randahl, Carl-Mikael Johansson, Stefan Barkaro, Bo Bokinge, Lars Karlsson
  • Publication number: 20040218754
    Abstract: In a line driver/receiver circuit where the line driver is connected with its output terminals to a load for supplying a transmit signal thereto and where the receiver is connected with its input terminals to the load for simultaneously receiving a receive signal therefrom, the transmit signal on the input terminals of the receiver is canceled by connecting the output terminals of the line driver to the load via equal complex sense impedances of an impedance value that is much smaller than the impedance value of the load impedance to match the load impedance, connecting the input terminals of the receiver to the load via equal first resistors and to respective output terminal of the line driver via equal second resistors, and providing transconductance amplifiers to sense the voltage across the sense impedances and supply corresponding currents to respective input terminal of the line driver.
    Type: Application
    Filed: April 9, 2004
    Publication date: November 4, 2004
    Inventors: Stefan Barkaro, Torbjorn Randahl
  • Publication number: 20040196873
    Abstract: To reduce power consumption of a first line driver/receiver (LD1) adapted to communicate with a second line driver/receiver (LD2) via a transmission line (1) in a multitone communication system, wherein, during a training sequence, the second line driver is adapted to transmit a known multitone signal pattern to the first line receiver, a signal processor (DSP1) connected to the first line driver/receiver (LD1) is adapted to measure the signal-to-noise ratio of the received signal pattern and, in response hereto, determine an appropriate bit rate to be used, to decrease the quiescent current of the first line driver in steps, to detect a decrease of the measured signal-to-noise ratio, and to set the quiescent current of the first line driver to the value it had before the decrease of the signal-to-noise ratio was detected.
    Type: Application
    Filed: May 25, 2004
    Publication date: October 7, 2004
    Inventor: Stefan Barkaro
  • Patent number: 6728366
    Abstract: For signal level adjustment of a multitone signal received over a transmission line (1) during a training sequence in a DSL system, a programmable high-pass filter (2) is connected to the transmission line (1). A programmable gain control unit (4) is connected between the filter (2) and an A/D converter (5). A digital signal processor (6) is connected with its inputs to the A/D converter (5), with control outputs (7, 9) to control inputs (8, 10) of the filter (2), and with control outputs (11, 13) to control inputs (12, 14) of the gain control unit (4). The processor (6) detects signal level differences between the highest and the lowest tone of the multitone signal and programs the filter (2) to make the signal levels of the highest and the lowest tone equal.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: April 27, 2004
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Stefan Barkarö, Albin Johansson
  • Patent number: 6687370
    Abstract: To secure an ADSL connection between a first ADSL transceiver (4) in a central office and a second ADSL transceiver (5) on a subscriber's premises on a telephone line (1) between a SLIC (2) in the central office and a telephone (3), a request to the SLIC (2) to apply a ringing signal to the telephone line (1) is detected. In response to such detection, the first ADSL transceiver (4) switches from a normal bit rate to a lower bit rate for the ADSL connection, and orders the second ADSL transceiver (5) to do the same before the ringing signal is applied. In response to an off-hook condition, the lower bit rate is maintained for the ADSL connection. In response to an on-hook condition after the off-hook condition as well as in response to a disappearance of the ringing request without an off-hook condition, the first ADSL transceiver (4) switches back to the normal bit rate and orders the second ADSL transceiver (5) to do the same.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: February 3, 2004
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Stefan Barkarö, Torbjörn Randahl
  • Patent number: 6636605
    Abstract: At the output of a line driver (1) connected to a long transmission line, signals received on the transmission line are only a fraction of signals transmitted by the line driver on the transmission line. To minimize the transmitted signal with its distortion and noise in the receive path of the line driver, an additional driver (4) having the same voltages and currents in the signal path, is added. The additional driver (4) drives an additional load (Z2). The signal transmitted to the transmission line together with its superimposed received signal, is subtracted from the signal from the additional driver (4), which is not superimposed on any received signal. The resulting signal is reduced from transmitted signal, transmitted distortion and transmitted noise. To minimize die size and power consumption, the additional driver (4) is scaled, but the distortion remains unchanged compared to the “normal” line driver.
    Type: Grant
    Filed: December 21, 1999
    Date of Patent: October 21, 2003
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Torbjörn Randahl, Stefan Barkarö
  • Patent number: 6625175
    Abstract: To secure an ADSL connection to an ADSL transceiver connected to a telephone line to be used also by an associated telephone, the telephone is normally kept disconnected from the telephone line and a predetermined number of bits is allocated to the ADSL connection. Upon an off-hook condition of the telephone in connection with an outgoing call, and upon a presence of a ringing signal on the telephone line or an off-hook condition of the telephone in connection with an incoming call, a predetermined lower number of bits is allocated to the ADSL connection before the telephone is connected to the telephone line.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: September 23, 2003
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Torbjörn Randahl, Stefan Barkarö
  • Patent number: 6542520
    Abstract: In an arrangement for securing an ADSL connection to an ADSL transceiver connected together with a telephone to a common telephone line; there are devices for setting a first number and a second, lower number, respectively, of bits to be allocated to the ADSL connection. Moreover, there are devices for detecting whether or not a ringing signal is present on the line and whether the telephone is in the off-hook or the on-hook condition. The first number of bits is allocated when neither the ringing signal nor the off-hook condition is detected, and the second, lower number of bits is allocated when the ringing signal and/or the off-hook condition is detected.
    Type: Grant
    Filed: May 6, 1999
    Date of Patent: April 1, 2003
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Stefan Barkarö, Albin Johansson
  • Patent number: 6407578
    Abstract: To reduce power dissipation in a line driver connected to a transmission line for transmitting multitone signals in the form of successive symbols separated by cyclic prefixes and generated by a digital signal processor, a controllable voltage supply is connected with its output terminal to a supply voltage terminal of the line driver. In response to an expected peak-to-peak value of the next symbol to be transmitted, the digital signal processor controls the controllable voltage supply during each cyclic prefix to set an appropriate supply voltage to the line driver.
    Type: Grant
    Filed: December 4, 2000
    Date of Patent: June 18, 2002
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventor: Stefan Barkarö
  • Patent number: 6167135
    Abstract: In generating a ringing signal of predetermined frequency and shape between the A- and B-wires to a subscriber's station in a telephone network, the ringing signal is directly injected in or superposed on the DC-levels of the wires. A voltage difference converting device converts any voltage difference between the A- and B-wires into a first current. A signal generating device generates a first voltage of the frequency and shape of the ringing signal to be generated, and a signal converting device then converts the first voltage into a second current. In a summation node the first current is subtracted from the second current to obtain a third current and this current is converted by passing it through a resistor to a second voltage. The second voltage is buffered and is again converted to a fourth current by applying the voltage to resistor. This fourth current is amplified by current amplifiers circuits comprising operational amplifiers, and is then supplied to the A-wire and drawn from the B-wire.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: December 26, 2000
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Stefan Barkaro, Torbjorn Randahl, Berndt Wallin, Sven Wiklund
  • Patent number: 5949224
    Abstract: A buck boost switching regulator includes a buck switch and a boost switch controlled by a first and second comparator, respectively. The first comparator generates a duty cycle control signal for the buck switch in response to the difference between the regulator output voltage and a control voltage corresponding to a desired regulator output voltage. The second comparator generates a duty cycle control signal for the boost switch in response to a supply voltage.
    Type: Grant
    Filed: August 5, 1998
    Date of Patent: September 7, 1999
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventor: Stefan Barkaro