Abstract: A WLAN transmitter capable of transmitting data signals modulated in accordance with an individual one of at least two different modulation schemes and corresponding methods and integrated circuit chips are provided. The WLAN transmitter contains a front end section having a low-IF topology and including a digital front end unit and an analog front end unit. The digital front end unit contains a first signal processing branch for processing transmission data signals modulated in accordance with a first one of said at least two different modulation schemes. The digital front end unit further contains a second signal processing branch for processing transmission data signals modulated in accordance with a second one of said at least two different modulation schemes. The analog front end unit contains one single signal processing branch for processing transmission data signals modulated in accordance with any one of said at least two different modulation schemes.

Abstract: A transmitter-receiver circuit and a method for distance measurement between a first node and a second node of a radio network is provided, wherein a mode of the first node and a mode of the second node are switched from a normal mode for communication in the radio network to a mode for distance measurement, wherein, in the mode for distance measurement for a transit time measurement, a radio signal is transmitted by the first node and received by the second node and a radio signal is transmitted by the second node and received by the first node and a first distance value is determined by measuring the transit time of the radio signals.

Abstract: A circuit, system, and method for range finding between two nodes of a radio network, in particular in conformance with the industry standard IEEE 802.15.4. A mode for finding the range to a second node is initiated by the first node. A command for range finding with the address of the second node is transmitted from the first node to the second node in the mode for range finding. The second node is switched into the range finding mode by the command. A sequence is controlled by the command in the range finding mode. As a result of the control by the command, a first signal is transmitted by the first node in a transmission time window of the sequence and the first signal is received by the second node in an associated reception time window of the sequence, and a first phase value of the first signal is measured.

Abstract: A system and method for distance measurement between two nodes of a radio network is provided. A first unmodulated carrier signal is transmitted by the first node and received by the second node. A second unmodulated carrier signal is transmitted by the second node and received by the first node. A first value and a second value of a first phase are measured by the first node, whereby the first value of the first phase is assigned to a first frequency of the received second carrier signal and the second value the first phase is assigned to a second frequency of the received second carrier signal, whereby the first frequency and the second frequency have a frequency difference.

Abstract: A dual band WLAN (Wireless Local Area Network) communications technique is provided where a frequency synthesizer unit generates an LO (Local Oscillator) signal at a frequency between both frequency bands and two downconversion units and/or two upconversion units are provided. One of the units performs conversion between the LO signal and an IF (Intermediate Frequency) signal while the other conversion takes place between the IF signal and a zero-IF or low-IF signal. Signal processing is performed on the zero-IF or low-IF signal.

Abstract: A dual band WLAN (Wireless Local Area Network) communications technique is provided where a frequency synthesizer unit generates an LO (Local Oscillator) signal at a frequency between both frequency bands and two downconversion units and/or two upconversion units are provided. One of the units performs conversion between the LO signal and an IF (Intermediate Frequency) signal while the other conversion takes place between the IF signal and a zero-IF or low-IF signal. Signal processing is performed on the zero-IF or low-IF signal.

Abstract: A circuit and method for operating a circuit is provided that includes a circuit section that has a number of memory elements, a first voltage regulator that can be connected or is connected to the circuit section in order to operate the circuit section, a second voltage regulator that can be connected or is connected to the circuit section in order to preserve an information item stored in the memory elements, a switching device that is connected to the circuit section and is designed to deactivate and activate inputs of the circuit section. The circuit being configured to control a deactivation and activation of the first voltage regulator and the deactivation and activation of the inputs of the circuit section.

Abstract: A method for the transmission and use of a power amplifier and transmission circuit of a radio network is provided that includes a power amplifier, which is connectable to an antenna, a counter whose output is connected to a control input of the power amplifier to output a count value to control the amplification of the power amplifier, a register for storing a register value, a comparator whose inputs are connected to the output of the counter and the register for comparing the register value with the count value, and a control circuit whose input is connected to the comparator and whose output is connected to the counter to control a counting process depending on the comparison result of the comparator.

Abstract: An operational amplifier and use of an operational amplifier is provided that includes an input differential amplifier, which is connected to a first input and to a second input and a differential output stage, which is connected to the input differential amplifier and a first output and a second output. The differential output stage has a first branch with two first transistors, whose drain and/or collector are connected to one another and to the first output. The differential output stage has a second branch with two second transistors, whose drain and/or collector are connected to one another and to the second output. The first gates and/or the first bases of the two first transistors in the first branch are connected to one another and to a first output of the input differential amplifier. The second gates and/or the second bases of the two second transistors in the second branch are connected to one another and to a second output of the input differential amplifier.

Abstract: A radio system for communication is provided that has a differential amplifier for amplifying a transmission frequency, particularly 2.4 GHz, wherein the differential amplifier has a first inductor, which is magnetically coupled to a second inductor, and a capacitor. The capacitor, the first inductor, and the second inductor are wired into a resonant circuit in such a way that the resonant circuit has a common-mode impedance for a common-mode signal and a push-pull impedance, different from the common-mode impedance, for the push-pull signal.

Abstract: An antenna diversity method and a corresponding communication device are disclosed that may be used in wireless LAN receivers. An AGC (Automatic Gain Control) unit controls a gain when processing signals received from antennae. A periodical switching process is performed between at least two antennae. During this periodical switching process, signals from each of the antennae are received alternately. The gain obtained by processing each received signal by means of the AGC unit is monitored and the obtained gain is compared with a predetermined threshold value. When for one of the at least two antennae the gain is below the predetermined threshold value, the periodical switching process is stopped and the antenna used at the time when stopping the periodical switching process is selected. This technique may provide an improved antenna diversity of low complexity, high performance and a short settling time.

Abstract: An operational amplifier and use of an operational amplifier is provided that includes an input differential amplifier, which is connected to a first input and to a second input and a differential output stage, which is connected to the input differential amplifier and a first output and a second output. The differential output stage has a first branch with two first transistors, whose drain and/or collector are connected to one another and to the first output. The differential output stage has a second branch with two second transistors, whose drain and/or collector are connected to one another and to the second output. The first gates and/or the first bases of the two first transistors in the first branch are connected to one another and to a first output of the input differential amplifier. The second gates and/or the second bases of the two second transistors in the second branch are connected to one another and to a second output of the input differential amplifier.

Abstract: A receiver, an integrated circuit chip and a method are provided for estimating the power of a digitally modulated signal received by the receiver in a communication system. The method comprises determining in-phase and quadrature-phase values of a phase constellation system relating to the received signal, calculating at least one modified in-phase value and at least one modified quadrature-phase value relating to the phase constellation system rotated by a predetermined angle, and determining absolute values of the in-phase and quadrature-phase values and the modified in-phase and quadrature-phase values. The method further comprises identifying the maximum of the absolute values, and determining a power estimate of the received signal based on the identified maximum value. The provided technique may allow for estimating the power of a digitally modulated signal in a simple and less complex implementation.

Abstract: A header detection technique for WLAN (Wireless Local Area Network) receivers is provided. The WLAN receiver comprises a signal processing unit that has analog circuitry and digital circuitry. There is further provided a header detection circuit for detecting a header in a received signal. The header detection circuit is comprised in the analog circuitry. In an embodiment, digital circuitry may be woken up based on a header detect signal that is generated by the header detection circuit. The embodiments may reduce the power consumption of the receiver, and the false detection rate.

Abstract: A WLAN (Wireless Local Area Network) communication device comprising a WLAN frequency synthesizer for generating a synthesizer signal suitable for modulating a transmission signal and/or demodulating a reception signal and corresponding methods and integrated circuit chips are provided. The WLAN frequency synthesizer comprises a reference oscillator for generating a first reference clock signal, a fractional-N PLL (Phase-Locked Loop) unit for receiving a second reference clock signal and converting the second reference clock signal into the synthesizer signal, and a frequency multiplier for receiving the first reference clock signal and converting the first reference clock signal into the second reference clock signal to be forwarded to the fractional-N PLL unit by multiplying the frequency of the first reference clock signal by a multiplication factor. Embodiments may provide shorter settling times and/or enhanced spurious suppression of the fractional-N PLL unit.

Abstract: A radio system for communication is provided that has a differential amplifier for amplifying a transmission frequency, particularly 2.4 GHz, wherein the differential amplifier has a first inductor, which is magnetically coupled to a second inductor, and a capacitor. The capacitor, the first inductor, and the second inductor are wired into a resonant circuit in such a way that the resonant circuit has a common-mode impedance for a common-mode signal and a push-pull impedance, different from the common-mode impedance, for the push-pull signal.

Abstract: An integrated circuit arrangement is provided for converting a high-frequency bandpass signal to a low-frequency quadrature signal with a first in-phase component and a first quadrature-phase component, which has: an amplifier arrangement, which is designed to generate an amplified signal and has a first amplifier stage for amplifying the high-frequency bandpass signal, a mixer unit with a first mixer to provide the first in-phase component and a second mixer to provide the first quadrature-phase component, and a driver amplifier, which is designed to generate a local oscillator signal. According to the invention, between the amplifier arrangement and the mixer unit a polyphase filter is disposed, which converts the amplified signal to a complex-valued polyphase signal with a second in-phase component and a second quadrature phase component.

Abstract: An integrated circuit comprises an ESD protection circuit including an inductor coupled between an input terminal and a ground terminal at which an RF signal is applied. The inductor is designed so as to provide a sufficient current capability required in typical ESD events. Moreover, the inductance of the inductor is selected to define, in combination with any parasitic capacitance present, a resonance tank with a resonant frequency that is matched to the RF signal. Accordingly, the operating frequency of the integrated circuit is not limited by the ESD protection circuit. In a further embodiment, an output terminal is ESD protected by an inductor that is coupled to an auxiliary voltage serving to bias an output transistor. Moreover, clamping elements, such as diodes, are provided between the auxiliary voltage and the supply voltage and between the auxiliary voltage and ground potential.

Abstract: An automatic gain controller for transceiver elements uses a digital topology to achieve an efficient and rapid gain settling so that an output signal of the variable gain section is within a predefined range. In one embodiment, an input signal is periodically sampled and latched so as represent the gain excess of a variable gain section. An accumulator, including an adder having saturation characteristics and a latch as a feedback element, creates a number for a new gain setting so that the variable gain section may adapt to the new gain setting within one clock period. In one example, a gain range of 84 dB is controllable and settling is achieved within 3 clock periods at most.

Abstract: A signal pre-processing device particularly in wireless LAN devices is provided that comprises an AGC (Automatic Gain Control) unit, an ADC (Analog-to-Digital Converting) unit and a normalization unit. The AGC unit amplifies a received analog input signal and outputs an amplified analog signal. Further, it automatically controls an amplification gain when amplifying the analog input signal. The ADC unit receives the amplified analog signal, converts it into a digital signal and outputs the digital signal. The normalization unit is receives the digital signal, applies a normalization function to the digital signal and outputs the normalized digital signal. Thus, less precise AGC units can be used, thereby reducing production costs as well as the size and complexity of the AGC unit. Further, shorter circuit development times are obtainable.