Abstract: A power amplifier system and method for locating carrier frequencies across a frequency band, identifying the modulation format of each carrier, and locating and suppressing undesired intermodulation distortion (IMD) products generated by the power amplifier. The system includes an amplifier for amplifying RF carrier signals in a main signal path, a variable phase shifter and variable attenuator on a feed forward path, and a tunable receiver that digitizes a portion of the frequency band to baseband. The tunable receiver includes a tunable voltage controlled oscillator which provides an oscillating frequency to a mixer and is phase-locked to a highly stable reference oscillator. The mixer downconverts a desired RF based on the oscillating frequency to IF. A filter passes only a selected portion of the IF signals, and the filter has a passband sufficient to discern both narrowband and wideband carriers and their associated IMD products.

Abstract: A receiver for receiving an amplitude shift keying signal includes: a threshold signal generating circuit that has a first diode to which a received amplitude shift keying signal is inputted and generates a threshold signal which practically follows a peak value of the amplitude shift keying signal; an input circuit including a second diode to which a received amplitude shift keying signal is inputted; a first comparator to which the amplitude shift keying signal that is outputted from the input circuit through the second diode is inputted, the first comparator acting with the threshold signal that is outputted from the threshold signal generating circuit through the first diode as a first threshold; a detection circuit for detecting output from the first comparator; and a second comparator to which output from the detection circuit is inputted, the second comparator acting with a second threshold that is a predetermined fixed value.

Abstract: A wireless signal amplification system including amplification apparatus (6) consisting of numerous different amplifiers (61 to 6n) which are distributed in an analogue processing chain (4). Also, a converter (12) for converting analogue signals into digital signals which, at input, are connected to the outlet of the analogue processing chain (4) and, at output, are connected to at least the gain control circuit (16) of the amplification apparatus (6) according to a value that is representative of a characteristic of the wireless signal (1). In this way, sampling of the wireless signal (1) by the converter (12) is optimized. The gain control circuit (16) establishes an average gain control signal (18), and also has, for each of the amplifiers (61 to 6n), a device for calculating an individual gain control signal (20i to 20n) according to a transfer function (H1 to Hn) which is specific to each amplifier and which is applied to the average gain control signal.

Abstract: A circuit arrangement for transmitting and receiving radio signals includes an amplification device with an output for transmitting signals, an input for receiving signals and a supply line, and an antenna for transmitting and receiving signals. The antenna is connected to the output of the amplification device. The output of the amplification device is an input for signals received via the antenna, and the supply line is an output for received signals that are converted to the supply line by the amplification device.

Abstract: A power amplification device includes an input for receiving a signal having a desired frequency band. The signal also has a transfer function associated therewith. The power amplification device further includes power amplification circuitry having an order greater than or equal to one, and signal amplifiers connected between the input and the power amplification circuitry. Each signal amplifier has a predetermined gain so that zeros of the transfer function are outside the desired frequency band.

Abstract: A method and apparatus for rapid alignment of adaptive feed forward power amplifiers are disclosed. Successful alignment settings are correlated with the operating conditions that affect the gain and phase of an amplifier. These operating conditions may include input power level, carrier frequency, temperature, DC supply voltage, or others. The successful alignment settings along with the corresponding operating conditions are stored in a list that is indexed using multi-dimensional attribute vectors. The elements of the list are generated automatically.

Abstract: A power amplifying apparatus for a mobile phone is provided. In the power amplifying apparatus, a power amplifier uses a transistor as a power amplifying device, and a non-volatile memory pre-records the static characteristic measurement data of the transistor. A DC bias current of the transistor is controlled according to transmission power of the power amplifier referring to the static characteristic measurement data, by changing a gate voltage of the transistor, by changing a drain voltage of the transistor with the gate voltage fixed, or by changing both the gate voltage and the drain voltage.

Abstract: A direct conversion receiver comprises a low noise amplifier, a bandpass filter, a mixer circuit and a baseband processing assembly. The low noise amplifier is capable of receiving communication signals from an antenna and, in turn, the bandpass filter is capable of filtering the received signals to a bandpass including a reception frequency band. The mixer circuit is electrically connected to an output of the bandpass filter, and can demodulate the received signals into differential signals in two channels. The baseband processing assembly is electrically connected to the mixer circuit opposite said bandpass filter. In this regard, the baseband processing assembly can process the demodulated differential signals in at least one of the channels. And to compensate DC offset from the demodulated differential signals, for each channel the baseband processing assembly includes a pair of dynamic offset compensation elements and a static offset compensation element.

Abstract: An unconditionally stable on-chip filter includes a filtering section and at least one negative resistance module. The filtering section is operably coupled to filter a signal and includes realizable integrated circuit passive components. The at least one negative resistance module is operably coupled to compensate for integrated circuit losses of the filtering section. The realizable integrated circuit passive components have values that are robust, in comparison to parasitic values, have minimal integrated circuit real estate, and provide realizable values for various integrated circuit manufacturing processes including CMOS technology.

Abstract: A head of transmission-reception of a high-frequency signal made in the form of an integrated circuit including a transmit amplifier and a receive amplifier. The transmit terminal of the transmit amplifier and the receive terminal of the receive amplifier are interconnected in a common transmit/receive terminal. The head includes means for selecting one of the amplifiers and means for placing the other amplifier in a high impedance state, as seen from the transmit/receive terminal.

Abstract: A Radio Frequency (RF) receiver includes a low noise amplifier (LNA) and a mixer coupled to the output of the LNA. The gain of the LNA is adjusted to maximize signal-to-noise ratio of the mixer and to force the mixer to operate well within its linear region when an intermodulation interference component is present. The RF receiver includes a first received signal strength indicator (RSSI_A) coupled to the output of the mixer that measures the strength of the wideband signal at that point. A second received signal strength indicator (RSSI_B) couples after the BPF and measures the strength of the narrowband signal. The LNA gain is set based upon these signal strengths. LNA gain is determined during a guard period preceding an intended time slot of a current frame and during a guard period following an intended time slot of a prior frame. The lesser of these two LNA gains is used for the intended time slot of the current frame.

Abstract: To provide an amplifying device which is reduced in size, weight and cost and which can improve the distortion compensation performance. In the amplifying device, input signals are each subjected to digital orthogonal modulation using an IF and further to offset rotation processing in digital orthogonal modulators, then bifurcated into a main signal system and a control system, and detection of a power value is performed at an IF band in a power detecting section of the control system. Therefore, offset rotation processing of the input signals in the power detection is not required, so that a structure for matching phases of a multi-carrier signal and a power value signal is not required, resulting in improving the distortion compensation performance without using an analog delay line.

Abstract: The invention relates to an amplification circuit AC comprising a plurality of amplification branches (Di, Hi, ai, where i=1 to N), each one of the branches having a gain proper that makes a contribution to the overall gain of the amplification circuit AC, the size of said contribution being determined by a control signal CNT.

Abstract: A power amplifier system and method for locating carrier frequencies across a frequency band, identifying the modulation format of each carrier, and locating and suppressing undesired intermodulation distortion (IMD) products generated by the power amplifier. The system includes an amplifier for amplifying RF carrier signals in a main signal path, a variable phase shifter and variable attenuator on a feed forward path, and a tunable receiver that digitizes a portion of the frequency band to baseband. The tunable receiver includes a tunable voltage controlled oscillator which provides an oscillating frequency to a mixer and is phase-locked to a highly stable reference oscillator. The mixer downconverts a desired RF based on the oscillating frequency to IF. A filter passes only a selected portion of the IF signals, and the filter has a passband sufficient to discern both narrowband and wideband carriers and their associated IMD products.

Abstract: A gain control circuit has a transmission power amplifier that amplifies a transmission signal to a predetermined level. An adjacent channel leak power ratio monitor finds a ratio of a distortion element corresponding to an adjacent channel leak power to a main element from an output signal supplied from the transmission power amplifier, and outputs the found ratio as an ACPR monitor value. A power supply control section variously controls power supply to the transmission power amplifier with use of the ACPR monitor value supplied from the adjacent channel leak power ratio monitor. A transmission signal level variable section controls a gain of a transmission signal path on the basis of a transmission level monitor value supplied from the adjacent channel leak power ratio monitor, thereby varying a level of the transmission signal.

Abstract: A transmission power amplifier unit of a base-station apparatus for compensating for non-linear distortion of a transmission power amplifier by feed-forward control is provided with a gain varying unit for varying gain of the transmission power amplifier unit. At start-up of the transmission power amplifier unit, a controller determines whether the base-station apparatus is in a blossoming mode or breathing mode, maximizes gain of the transmission power amplifier unit by controlling the gain varying unit if the mode is the blossoming mode and increases the gain gradually in proportion to the passage of time if the mode is the breathing mode.

Abstract: In accordance with the present invention, a method is disclosed for preventing noise spikes due to abrupt changes of a transmission signal in a cordless telephone. The method is comprised of two sub-methods where a first sub-method for controlling the gain of a transmission signal when a call is initiated, and a second sub-method for controlling the gain of a transmission signal when a call is terminated.

Abstract: A variable gain amplifier device controlled by a first gain control signal comprises a gain controlled amplifier having a gain and including a differential pair of first and second MOS type transistors configured to operate in a weak inversion region; and a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal.