Abstract: The invention pertains to a method and an arrangement for linearizing a radio receiver (20). The invention is advantageously applied in the reception circuits of mobile stations. A receiver according to the invention monitors the signal strength on the receive channel and its neighboring channels. In addition, the receiver can determine the quality of the detected signal by calculating its bit error ratio or signal-to-noise ratio. In normal conditions, i.e. when the signal strength is satisfactory on the receive channel and normal on the neighboring channels, the supply currents of the front-end amplifiers (A1, A2) and at least the first mixer (M1) of the receiver are kept relatively small. If the signal strength on the receive channel goes below a predetermined value or, on a neighboring channel, exceeds a predetermined value, said supply currents are increased. This may happen also if the bit error ratio or signal-to-noise ratio reaches a predetermined limit.

Abstract: The disclosed invention provides a wireless communication receiver that is able to lessen the effect of noise that accompanies gain change by programmable gain amplifiers. Such noise is produced when direct conversion type programmable gain amplifiers by which gains are adjustable in steps are used for gain control of signals of CDMA or the like in which reception is not intermitted.

Abstract: Systems and methods are provided for reducing the peak to average ratio of signals, so that the signals can be amplified more efficiently. An error signal that corresponds to crests of the input signal is generated, and subtracted from the input signal. When a crest is so long that it corresponds to more than one sample, only the maximum sample contained in the crest is used to form the error signal. Optionally, multiple stages of decresting may be implemented sequentially.

Abstract: A wireless or wired communication system and method is provided including a transmitter and a receiver. A RF communication system in accordance with the present invention includes an apparatus and gain control method between RF receiver and baseband modem in case of a plurality of gain stages inside a receiver. The gain of each stage can be controlled by an integrated gain controller. The gain controller monitors the signal level of each gain stage to place its gain to optimal value. The gain control apparatus and method can be implemented in a digital AGC system. The gain controller accepts a signal implementing gain control and thus there is no stability issue. When distributed gain stages are present inside a related art receiver and separate gain control loops are used, stability issues can arise. In a preferred embodiment of an apparatus and method, the baseband modem decides the amount of gain control and adjusts the gain of certain gain stages by the proper amount.

Abstract: A high frequency power amplifying apparatus is provided with an amplifying section with a plurality of amplifying stages connected in cascade. A power control signal is supplied to the amplifying section through a control terminal so as to control the output of the high frequency power amplifying apparatus. Each of the amplifying stages has a gain smaller than that of a preceding stage. Gain control signals generated from the power control signal are supplied to the respective amplifying stages. Dividing resistors are connected in series with one another between the control terminal and a reference potential so as to divide the voltage of the power control signal to thereby generate a plurality of different gain control signals. Different ones of the gain control signals are supplied to the respective amplifying stages, an absolute value of a voltage of the gain control signal applied to each stage is smaller than that applied to an earlier preceding stage.

Abstract: A high frequency power amplifying apparatus is provided with an amplifying section with a plurality of amplifying stages connected in cascade. A power control signal is supplied to the amplifying section through a control terminal so as to control the output of the high frequency power amplifying apparatus. Each of the amplifying stages has a gain smaller than that of a preceding stage. Gain control signals generated from the power control signal are supplied to the respective amplifying stages. Dividing resistors are connected in series with one another between the control terminal and a reference potential so as to divide the voltage of the power control signal to thereby generate a plurality of different gain control signals. Different ones of the gain control signals are supplied to the respective amplifying stages, an absolute value of a voltage of the gain control signal applied to each stage is larger than that applied to an earlier preceding stage.

Abstract: Automatic gain control (AGC) methods and apparatus suitable for use in orthogonal frequency division multiplexing (OFDM) receivers are described. One AGC method includes the steps of repeatedly performing a first AGC process which adjusts amplifier gain based on determining that a signal level of multiple time sample values is outside a limit set by a first predefined threshold; and repeatedly performing a second AGC process which adjusts the amplifier gain based on determining that a signal level of multiple frequency sample values associated with a plurality of pilot tones is outside a limit set by a second predefined threshold. Preferably, the first AGC process is performed repeatedly at a first rate and the second AGC process is performed repeatedly at a second rate that is less than the first rate.

Abstract: A device and method for controlling an output power level in a mobile communication terminal. The device includes an RSSI detector for detecting a strength of a signal received from a base station, and a controller having a memory for storing bias voltage control values and bias current control values corresponding to strengths of received signals, wherein the controller reads the corresponding bias voltage control value and bias current control value in response to the detected signal strength and supplies the read values to a power amplifier.

Abstract: A converter for the direct down-conversion of direct broadcast satellite signals such as those used for digital television. The direct broadcast satellite signal received from the satellite dish is amplified and then downshifted within the Low Noise Block (LNB), a subsystem contained with the satellite dish assembly, to a predetermined frequency band, typically in the L-band in the range 950 MHz to 2150 MHz. The signal is then sent via a coaxial cable to the set-top box unit located indoors, and there directly converted from the received frequency to baseband, in one embodiment by a single integrated circuit comprising a variable gain amplifier (VGA), frequency synthesizer, a quadrature generator and a plurality of mixers.

Abstract: In a radio front-end circuit having at least two amplifier-mixer cascades, the amplifiers are switched on or off via the mixers. By switching between the amplifier-mixer cascades, the power consumption is lowered.

Abstract: A variable gain amplifier includes multiple unit variable gain amplifiers connected in series which amplify an input signal in accordance with their respective gains and generate a multi-stage amplified signal. A gain control circuit generates voltage control signals, one for each of the unit amplifiers, from a gain control input signal. The control signals control the respective gains of the unit amplifiers such that the gain of the first amplifier in the series is greater than the gain of the last amplifier in the series.

Abstract: An automatic gain control apparatus (106) and method for a radiotelephone receiver employs stored inverse transfer function data (400) of the radiotelephone receiver and a gain estimation circuit (200). The gain estimation circuit (200) estimates the input power of received signal (103) and determines a required gain based on a nonlinear portion of the inverse transfer function data (400) of the radiotelephone receiver to provide an improved dynamic range of the receiver. The apparatus and method performs convergence within one iteration to perform fast gain control. In addition, if desired, a DC offset compensation circuit, such as a feedforward DC offset compensation circuit (202), compensates the digital representation of the input signal for use by the gain estimation circuit (200).

Abstract: Described herein is an analog-digital broadcast shared receiving tuner for receiving therein a low-level broadcast signal of a digital broadcast assigned to a vacant channel of an analog broadcast and having first and second frequency conversion stages each comprised of a frequency mixer and a local oscillator. A variable attenuator capable of performing switching between predetermined attenuation and zero attenuation is electrically connected between an intermediate frequency amplifier for amplifying a first intermediate frequency signal outputted from the first frequency conversion stage and the frequency mixer of the second frequency conversion stage, which follows the intermediate frequency amplifier, so that the attenuation of the variable attenuator reaches zero attenuation upon reception of an analog broadcast and the attenuation thereof reaches predetermined attenuation upon reception of a digital broadcast.

Abstract: An amplifier for amplifying a high frequency signal includes comprises cascade-connected an input npn transistor and an output npn transistor and a bias circuit to control a base current Ib of the input transistor in order to make a DC component of a collector current Ic of the cascade-connected npn transistors constant. A shunt transistor is further connected between a base electrode of the input npn transistor and one terminal of a power source and is connected so that the base current of the input npn transistor flows through a resistor connected between a base electrode and an emitter electrode of the shunt transistor. By lowering a base voltage of the output npn transistor in response to a gain control signal, the collector current Ic is reduced, and a gain of the amplifier is reduced, and simultaneously the shunt transistor is made in shunting operation.

Abstract: An AGC amplifier control circuit applying for both transmission and reception which the quantity of data memorizing in a memory is decreased and the address of the memory is simplified is provided. The AGC amplifier control circuit provides RF attenuators controlled in hysteresis and these RF attenuators are driven at the next gain renewing time of AGC amplifiers and provides attenuation controllers outputting the information whether the RF attenuators have a fixed attenuation quantity or not. In this construction of circuit, memories memorize the control voltage data of the gain of the AGC amplifiers with the relation of desired outputs, at the time when the RF attenuators are driven and have a fixed attenuation quantity, data conversion circuits convert the data to make the gain of the AGC amplifiers increase corresponding to these attenuation quantities.

Abstract: An attenuator unit for attenuating a signal, the unit includes a &pgr;-type attenuator having a first resistor and second and third resistors which are arranged on both sides of the first resistor, a first transistor connected in parallel with the first resistor, and a second transistor connected between a joint node of the second resistor and the third resistor and a first voltage level. In the unit, by controlling a gate voltage of the first transistor and a gate voltage of the second transistor, an attenuation value of the attenuator unit is changed.