Showing papers by "Aarno Parssinen published in 2002"

Method and apparatus for continuously controlling the dynamic range from an analog-to-digital converter

Abstract: A method for continuously determining the required dynamic range for an analog-to-digital converter by determining the received signal strength and using this received signal strength value in combination with the overall dynamic range for the ADC and the target resolution of the ADC to decode a radio channel in the absence of interference, wherein the target resolution is also related to the type of decoding to be performed subsequent to analog-to-digital conversion. The method allows for a reduction in power consumption associated with the ADC, especially when the incoming signal is received with few interfering radio channels and with a relatively high signal strength. The present method can be combined with gain control and analog alert detection.

Method and apparatus for scaling the dynamic range of a receiver for continuously optimizing performance versus power consumption

Abstract: Methods and apparatus are disclosed for operating a RF receiver. The method executes, during operation of the RF receiver, by periodically determining existing RF receiver operational conditions; determining RF receiver performance requirements based at least in part on the determined existing RF receiver operational conditions; and by allocating power consumption between RF receiver functional blocks in accordance with the determined RF receiver performance requirements and in accordance with a behavior model of at least one of the RF receiver as a whole and individual functional blocks of the RF receiver. The method may also monitor the resulting RF receiver signal quality to determine if allocation of power consumption has resulted in an optimum allocation of the power consumption.

Calibration techniques of active BiCMOS mixers

Abstract: This paper describes calibration techniques for downconversion mixers used in integrated direct-conversion receivers. A method of achieving a high even-order intermodulation rejection is presented. Using the method presented, the receiver second-order input intercept point (IIP2) can always be improved by more than 20 dB. The minimum achieved receiver IIP2 after calibration is +38 dBm. A technique to enhance the I/Q-amplitude balance between the quadrature channels is also introduced. A single-balanced adjustable mixer is implemented as a part of a prototype direct-conversion receiver. The receiver chip consists of a low-noise amplifier, mixers and calibration circuitry, a divide-by-two circuit, local oscillator (LO) buffers for LO generation, and active baseband filters. The chip is fabricated using a 0.35-/spl mu/m SiGe BiCMOS process and is characterized at 900 MHz.

Communication system, a communication device and a method for performing communication

Abstract: The present invention relates to a communication system comprising devices (2 a -2 d) having means for short range communication using a certain frequency band. The frequency band is divided into communication channels. In the communication system some of said communication channels are predefined for establishment of the connection and other communication channels are predefined for data transfer between at least two devices. The present invention also relates to a communication device for communication in a communication system, the device having means for short range communication using a certain frequency band, which is divided into communication channels. The present invention further relates to a method for performing communication in a communication system comprising devices, which have means for short range communication using a certain frequency band, which is divided into communication channels.

Method and apparatus for reducing power consumption in transceivers in wireless communications systems having a power control loop

Abstract: An apparatus (100) and corresponding method for use by a first transceiver in saving power when communicating over a wireless communication system with a second transceiver, the first having an operating cycle including an interval in which it sends transmit power requests to the second, the transmit power requests being made based on measurements of the signal received by the first and performed in an interval of the operating cycle in which the operational parameters correspond to a power control measurement state. The method includes: when no power control measurements are being made, a step (44b) of enabling receiver tuning to adjust the receiver operational parameters to place the receiver in a less power-consuming internal state.

RF gain control in direct conversion receivers

Abstract: This paper presents a study of LO self-mixing and RF gain control issues in direct conversion receivers. In cellular systems, that use continuous time frequency duplexing, these can constitute serious problems. The presented topic is of special importance when digitally programmable gain is implemented at the RF frequencies before the downconversion mixers, practically in the LNA. Furthermore, this paper gives circuit solutions to overcome this problem.

Method and apparatus for scaling the dynamic range of a receiver

Abstract: Methods and apparatus are disclosed for operating a RF receiver. The method executes, during operation of the RF receiver, by periodically determining existing RF receiver operational conditions; determining RF receiver performance requirements based at least in part on the determined existing RF receiver operational conditions; and by allocating power consumption between RF receiver functional blocks in accordance with the determined RF receiver performance requirements and in accordance with a behavior model of at least one of the RF receiver as a whole and individual functional blocks of the RF receiver. The method may also monitor the resulting RF receiver signal quality to determine if allocation of power consumption has resulted in an optimum allocation of the power consumption.

A SiGe RF front–end with on–chip VCO for a GPS receiver

Abstract: A GPS direct conversion RF front-end with on-chip VCO fabricated in 0.35µm SiGe BiCMOS technology is presented. The properties of inductively degenerated common-emitter LNA and resistively degenerated Gilbert downconversion mixer are examined. The approximative equations for the front-end DSB-NF and IIP3 are given. By applying the derived formulas, the front-end performance can be readily estimated and optimized. The implemented RF front-end has a voltage conversion gain of 25.8 dB, DSB-NF of 2.7 dB, IIP3 of-14.5 dBm and IIP2 of +26 dBm. The 3.15 GHz VCO has a phase noise of -99 dBc/Hz at 100 kHz offset. The front-end draws 15.3 mA from a 2.7 V supply.

System, method and device for performing communication in a short range radio network

Abstract: The present invention relates to a communication system comprising devices (2a-2d) having means for short range communication using a certain frequency band. The frequency band is divided into communication channels. In the communication system at least a first device class and a second device class are defined for categorizing the devices. The device class determines at least which communication channels the device can use in communication.

Radio receiver using a feedback loop to compensate i/q amplitude errors, and method

Abstract: The invention relates to a quadrature demodulating radio receiver and to a method for reducing an imbalance in gain between an in-phase channel and a quadrature channel of such a radio receiver. Received radio frequency signals are downconverted to in-phase and quadrature-phase signals, either to a baseband or a certain IF frequency. In order to improve the performance of the channels, it is proposed that imbalances in gain or amplitude between the two channels are compensated in the analog domain. This is achieved by employing in at least one of the channels amplifying means with an adjustable gain for amplifying received signals in the analog domain, the adjustable gain being controlled according to a detected imbalance in gain. The invention moreover relates to an equivalently designed radio transmitter and a corresponding method. The invention equally relates to components and communications systems including such a radio receiver or transmitter, and to a transconductance mixer for such a radio receiver or transmitter.