Nokia Corporation

Nokia Mobile Phones Limited

Jarmo J Heinonen

Sami Vilhonen

Jyrki Koljonen

Markus Pettersson

Kai Leino

Vesa Viitaniemi

Terho Kaikuranta

Jakke Mäkelä

Jaakko A Hulkko

Lars Henrik Mucke

Tom Mikael Ahola

Pekka Naula

Pertti Kangas

Toivo Vilmi

Matti Alen

Karl-Erik Gustafsson

Sami Vihonen

Jussi Salminen

Matti Ahonen

Torsti Halonen

Mika Kaustinen

Kari Vigelius

A direct-conversion radio receiver is provided. The receiver includes a first measurement unit configured to measure a signal level of a received signal at an input of the receiver. The receiver also includes a gain controller configured to stepwise adjust at least a front-end gain and a baseband gain of the receiver when the signal level of the received signal at the input of the receiver exceeds a given sensitivity level, and adjust the front-end gain with at least one further gain step when the input signal level is below the given sensitivity level.

Increasing sensitivity of radio receiver

Disclosed is an oscillator circuit () for use in a local oscillator of an RF communications device () that communicates over an RF channel. The oscillator circuit includes an oscillator transistor coupled to a power supply voltage (Vcc) through a buffer transistor, and a biasing network having bias voltage outputs coupled to a control input of the oscillator transistor and to a control input of the buffer transistor. In one embodiment the bias voltage network is coupled to Vcc, while in another embodiment the bias voltage network is coupled to a separate voltage (Vbias). Circuitry is provided for setting a magnitude of Vcc and/or Vbias as a function of at least one of RF channel conditions, such as channels conditions determined from a calculation of the (SNR), or an operational mode of the RF communications device.

Oscillator having controllable bias modes and power consumption

The invention relates to a mobile radio-frequency enabled device. In order to enable a lightning detection by means of such a device, it comprises an electromagnetic interferences detection component detecting electromagnetic interferences in at least one radio-frequency channel, which at least one radio-frequency channel is usable by the mobile radio-frequency enabled device for a communication link. The device further comprises a processing component adapted to determine whether a lightning stroke can be assumed to have occurred in the vicinity of the mobile radio-frequency enabled device due to an electromagnetic interference detected by said electromagnetic interferences detection component. The invention relates equally to a corresponding system, to a corresponding method and to a corresponding software program product.

Detection of lightning

Disclosed is an oscillator circuit () for use in a local oscillator of an RF communications device () that communicates over an RF channel. The oscillator circuit includes an oscillator transistor coupled to a power supply voltage (Vcc) through a buffer transistor, and a biasing network having bias voltage outputs coupled to a control input of the oscillator transistor and to a control input of the buffer transistor. In one embodiment the bias voltage network is coupled to Vcc, while in another embodiment the bias voltage network is coupled to a separate voltage (Vbias). Circuitry is provided for setting a magnitude of Vcc and/or Vbias as a function of at least one of RF channel conditions, such as channels conditions determined from a calculation of the (SNR), or an operational mode of the RF communications device. The magnitude of Vcc (and Vbias) may be set between about zero volts (i.e., turned off) and some maximum value. The operational mode can be, for example, one of a TDMA, burst-type narrow bandwidth mode, or a CDMA, substantially continuous, wider bandwidth mode. The value of Vcc and/or Vbias maybe set so as to minimize power consumption as a function of an amount of allowable local oscillator phase noise. A broad bandwidth/narrow bandwidth dual mode RF transceiver in accordance with these teachings includes at least one phase locked loop (PLL) that includes a voltage controlled oscillator (VCO) providing a local oscillator signal for at least one of an I/Q modulator or an I/Q demodulator; a processor responsive to an output of said I/Q demodulator for determining at least one aspect of RF channel quality; and circuitry coupled between the processor and the VCO for minimizing at least VCO power consumption as a function of an amount of allowable VCO phase noise for a current RF channel quality.

Dual mode voltage controlled oscillator having controllable bias modes and power consumption

Disclosed is a method for operating a mobile station () that includes an RF receiver () having an RF front end (A) followed by a base band section (B). The base band section includes an AGC block (') that contains a DC blocking capacitor (C) coupled in series between an input node (Vin) of the AGC block and an input to a gain element (A). The method has steps of tuning from a current RF channel to another RF channel to make a signal strength measurement, and reducing a time constant of the AGC circuit by shorting around the DC blocking capacitor. Also disclosed is a method for operating the mobile station where the base band section includes the AGC block that contains an AC coupling capacitance coupled in series with a first resistance (R) between an input node of the AGC block and an input to the gain element. This method has steps of operating the AC coupling capacitance and the first resistance as a first order low pass filter for attenuating the AC value of an input signal, and closing at least one switch for switching in additional capacitance and resistance for transforming the first order low pass filter to a second order low pass filter for increasing the attenuation of the AC value of the input signal. In these various embodiments circuit topologies are described for both inverting and non-inverting operational amplifier implementations.

Direct conversion receiver architecture

The invention relates to an enhanced shielding arrangement. A shielding arrangement comprises a shielding can and a layered printed circuit board having electrical components and at least two ground potential layers. There are grounding connections between edges of the shielding can and at least one of the ground potential layers, and grounding connections between components inside the shielding can and at least one of the ground potential layers, so that the two grounding connections are connected to each other only through at least one of the ground potential layers for providing small loops.

Shielding arrangement

The invention relates to a phase-locked loop structure providing local oscillator signals. In order to enable an improved supply of local oscillator signals, the phase-locked loop structure comprises a first phase-locked loop including a first voltage controlled oscillator and a second phase-locked loop including a second voltage controlled oscillator. A first local oscillator output provides a first local oscillator signal, wherein a signal output by the first voltage controlled oscillator is forwarded to the first local oscillator output. A second local oscillator output provides a second local oscillator signal. A selection component forwards a signal output by the first voltage controlled oscillator or a signal output by the second voltage controlled oscillator to the second local oscillator output. The invention relates equally to a corresponding communication unit and to a corresponding method.

Provision of local oscillator signals

A module for detachable connection to a telephone and a telephone employing such a module. The module includes a device for generating a silent alarm and a system for actuating the silent alarm when connected to the telephone for indicating an incoming call. A pin which provides information about the temperature of the module during charging provides the connection for actuating the silent alarm.

Telephone and module having a pin for providing temperature information and generating a silent alarm

The object of the invention is a transmitter/receiver for transmitting and receiving of an RF signal in two frequency bands. In the solution according to the invention, a transmitter/receiver is used which is based on direct conversion and in it, when operating in both frequency bands, the mixing frequency is formed by means of the same synthesizer (340). This is implemented preferably in such a way that in the higher operating frequency, the frequency of the output signal of the synthesizer is used as such as a mixing frequency and when operating in the lower operating frequency, a mixing frequency is used which is obtained by dividing the frequency of the output signal of the synthesizer by two or a larger integer in the divider (311, 361). When the solution according to the invention is used, many synthesizers are not needed in the transmitter/receiver and no intermediate frequency components are needed.

Transmitter/receiver for transmitting and receiving of an RF signal in

This invention teaches a method, and circuits that operate in accordance with the method, for adaptively controlling the transmitted power of a CDMA transmitter (50, 102). The method includes the steps of: (a) presetting a register, such as a counter (112), with an estimate of a maximum transmitter gain signal, the counter having an count output that is a representation of a maximum transmitter gain signal (TX max); (b) deriving a transmitter gain signal (TX gain) from a received CDMA signal; (c) comparing TX max to TX gain and, if TX gain is greater than TX max, (d) applying a gain control signal to the transmitter that is derived from TX max, and (e) enabling the counter to increase its count; else, if TX gain is less than TX max, (f) applying a gain control signal to the transmitter that is derived from TX gain, and (g) disabling the counter from increasing its count.

Spread spectrum radiotelephone having adaptive transmitter gain control

A dual mode transmitter circuit is disclosed including a non-linear high-power amplifier having an amplification that can be adjusted and a linear high-power amplifier. A first switch and a second switch are connected to the input and output of the linear, high-power amplifier. An amplification-adjustable, high-frequency transmitter control amplifier is connected to the input of the non-linear high-power amplifier. Apparatus for measuring transmission power such as a directional coupler is connected to the second switch, and a duplex filter is connected to the directional coupler. A power level control circuit is responsive to the measured transmission power from the directional coupler and to a power level signal. The power level signal is representative of the desired output power of the transmitter. The power level control circuit compares the measured power level from the directional coupler with the desired power level and produces a difference signal on its output lead which is connected to both the non-linear high-power amplifier and to the high-frequency transmitter control amplifier. A mode selection signal, for designating either an analog or digital type transmission mode is applied to a mode control circuit that is responsive to the mode selection signal and provides switching signals to the first and second switches and a control signal to the linear amplifier. The mode selection signal sets the transmitter to function in either the non-linear transmission (analog) mode or the linear transmission (digital) mode.

Dual mode transmission system with switched linear amplifier

The present invention relates to a circuit arrangement by which a voltage-controlled temperature-compensated oscillator (VCTCXO) (10) serving as the frequency reference in a radio telephone is controlled. In the circuit arrangement there is used a phase-locked loop which locks the frequency of the VCTCXO (10) to the frequency of the intermediate-frequency signal (2.IF) of the receiver of the telephone. When the telephone is started up, a constant setting voltage (30) is coupled as the control signal (V.sub.con) for the VCTXCO (10) for controlling the reference frequency. In the call state the control signal (V.sub.con) is provided by by the phase-locked loop in which the locking is to the frequency of the intermediate frequency signal. When the call is cut off the control voltage (V.sub.con) is supplied from a memory (26) coupled to the phase-locked loop in which the value of the control signal (V.sub.con) is substantially equal to the control signal (V.sub.con) supplied by the phase-locked loop at the moment of cut-off, and which has been stored in the memory (26).

Circuit arrangement for automatic frequency control in a radio telephone

A synthesizer for a radio transceiver uses a Direct Digital Synthesis (DDS) system (3) to provide a modulated signal for the transmitter section. The modulated signal (So) is then mixed in a mixer (4) using a signal from a local oscillator (1) to provide the signal for transmission. The reference frequency for the DDS system is provided by the local oscillator (1) of the receiver section. The local oscillator is used to provide the signal for the mixer (4).

Direct digital synthesizer for producing a modulated intermediate

A hand-held transceiver comprises a base element and an amplifying element between which there is a defined interface, whereby the beam element may alternatively be connected with the separate amplifier through the above mentioned interface. Due to the modular structure of the hand-held transceiver, it is possible to make a car radio telephone where the hand-held transceiver connected to the amplifier only comprises the base element.

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Salo, Finland

Jarmo J Heinonen