Abstract:
A method for processing a plurality of signals may include amplifying an input signal and generating a wideband signal from the amplified input signal. The method may further include bandpass filtering the generated wideband signal to generate a narrowband signal, and adjusting amplification of the input signal based on a narrowband received signal strength indication of the generated narrowband signal, and/or a wideband received signal strength indication of the generated wideband signal. The amplified input signal may be downconverted to generate the wideband signal. The amplified input signal may be downconverted to an intermediate frequency (IF) and/or to a baseband signal to generate the wideband signal. At least one blocker signal may be bandpass filtered from the amplified input signal.
Abstract:
In a high frequency power amplifier circuit that supplies a bias to an amplifying FET by a current mirror method, scattering of a threshold voltage Vth due to the scattering of the channel impurity concentration of the FET, and a shift of a bias point caused by the scattering of the threshold voltage Vth and a channel length modulation coefficient λ due to a short channel effect are corrected automatically. The scattering of a high frequency power amplifying characteristic can be reduced as a result.
Abstract:
In order to compensate for performance degradation caused by inferior low-cost analog radio component tolerances of an analog radio, a future system architecture (FSA) wireless communication transceiver employs numerous digital signal processing (DSP) techniques to compensate for deficiencies of such analog components so that modern specifications may be relaxed. Automatic gain control (AGC) functions are provided in the digital domain, so as to provide enhanced phase and amplitude compensation, as well as many other radio frequency (RF) parameters.
Abstract:
An amplifier comprises a first amplifier circuit which amplifies a first signal to output an amplified first signal, a circuit which outputs a second signal corresponding to a difference between the first signal and the amplified first signal, a second amplifier circuit which amplifies the second signal to output an amplified second signal, a combine circuit which outputs an amplified signal by combining the amplified second signal with the amplified first signal, and a controller which controls a supply of a power to the first amplifier circuit and the second amplifier circuit and has a first mode to supply the power to the second amplifier circuit without supplying the power to the first amplifier circuit.
Abstract:
A low noise amplifier circuit (10) includes an attenuator (12) for receiving a calibration signal and generating an attenuated calibration signal. A low noise amplifier (14) amplifies the attenuated calibration signal in calibration mode or amplifies a functional signal in functional mode. In calibration mode, a envelope detector/comparator (16) compares the calibration signal with the output of the low noise amplifier and generates a compensation signal indicating a deviation between the two signals. The gain of the low noise amplifier is adjusted responsive to the compensation signal.
Abstract:
In a high frequency power amplifier circuit in which bias voltages are applied to the transistors for amplification by current mirroring, this invention enables preventing waveform distortion near the peak output power level by allowing sufficient idle currents to flow through the transistors for amplification, while enhancing the power efficiency in a low output power region. The power amplifier includes a detection circuit comprising a transistor for detection which receives the AC component of an input signal to the last-stage transistor for amplification at its control terminal, a current mirror circuit which mirrors current flowing through that transistor, and a current-voltage conversion means which converts current flowing in the slave side of the current mirror circuit into a voltage. In the detection circuit, a voltage from a bias circuit for generating the bias voltages for the transistors for amplification is applied to the control terminal of the transistor for detection and output of the detection circuit is applied to the control terminal of the last-stage transistor for amplification.
Abstract:
An automatic gain control (AGC) circuit includes a number of attenuation circuits connected in series relative to a reception signal, a of variable gain amplifiers to which the reception signal and each output signal from the attenuation circuits are fed, respectively, a signal deriving circuit connected to output terminals of the variable gain amplifiers for deriving a level-controlled output signal, and a control current generating circuit for generating a control current having a predetermined characteristic out of first and second AGC voltages, wherein the control current outputted from the control current generating circuit is supplied to the variable gain amplifiers as a control signal for switching an operation thereof and for controlling a gain thereof, and a feedback control current corresponding to the control current is performed by the control current generating circuit.
Abstract:
The invention provides an automatic gain control and antenna selection method used in a receiver of a radio communication system. The received signal power is estimated by digital signal processing after analog-to-digital conversion in the system, in order to adjust the gain of the front end analog signal until the magnitude of the analog signal is adjusted to an optimum range of the digital signal processing. In addition, the ADC is utilized to estimate the signal power as the basis of the antenna selection.
Abstract:
A Variable Gain Amplifier (VGA) amplifies an input signal according to a gain, to produce an amplified signal. A detector module detects a power indicative of a power of the amplified signal. A comparator module compares the detected power to a high threshold, a low threshold and a target threshold intermediate the high and low thresholds. A controller module changes the gain of the VGA so as to drive the detected power in a direction toward the middle threshold when the comparator module indicates the detected power is not between the high and low thresholds.
Abstract:
A dynamically varying linearity system nullDVLSnull capable of varying the linearity of a radio frequency (RF) front-end of a communication device responsive to receiving a condition signal indicating a desired mode of operation of a transmitter. The DVLS may include a condition signal indicative of the desired mode of operation and a controller that adjusts the linearity of the transmitter responsive to the condition signal. The condition signal may be responsive to a user interface. The controller, responsive to the condition signal, may dynamically adjust the operating current of the transmitter.