Abstract: The object of this invention is to reduce the cost of an amplification device that has a distortion detection loop that uses an amplifier to amplify the signal subject to amplification and detect the distortion arising in said amplifier, and a distortion removal loop that removes the distortion detected by the distortion detection loop from the signal amplified by said amplifier.

Abstract: A feed forward type distortion compensation amplification apparatus, which includes a distortion detection loop and a distortion compensation loop, cancels a first distortion element generated from the distortion detection loop by a second distortion element generated from the distortion compensation loop to generate an output signal, and controls bias levels of the main amplifier and the error amplifier based on a level of the output signal. An adaptive pre-distortion type distortion compensation amplification apparatus includes a detection unit for detecting an input power level, a control unit for storing the input power level and a bias level corresponding thereto and generating the bias level in response to the input power level, and a bias control unit for applying a bias to an amplifier unit in response to the bias level.

Abstract: The object of this invention is to provide a feedforward amplifier that performs precise distortion compensation on a plurality of signal groups without adopting broadband frequency-band characteristics for the auxiliary amplifier. This is achieved by inputting a plurality of signal groups, each having a different frequency bandwidth respectively. In a distortion detection loop, a main amplifier 4 is used to amplify this plurality of input signal groups and detect the distortion arising in said main amplifier 4. In a distortion compensation loop the distortion detected in the distortion detection loop is removed from the amplified signal from said main amplifier 4.

Abstract: A feed forward type distortion compensation amplification apparatus, which includes a distortion detection loop and a distortion compensation loop, cancels a first distortion element generated from the distortion detection loop by a second distortion element generated from the distortion compensation loop to generate an output signal, and controls bias levels of the main amplifier and the error amplifier based on a level of the output signal. An adaptive pre-distortion type distortion compensation amplification apparatus includes a detection unit for detecting an input power level, a control unit for storing the input power level and a bias level corresponding thereto and generating the bias level in response to the input power level, and a bias control unit for applying a bias to an amplifier unit in response to the bias level.

Abstract: The object of this invention is to provide a feedforward amplifier that performs precise distortion compensation on a plurality of signal groups without adopting broadband frequency-band characteristics for the auxiliary amplifier. This is achieved by inputting a plurality of signal groups, each having a different frequency bandwidth respectively. In a distortion detection loop, a main amplifier 4 is used to amplify this plurality of input signal groups and detect the distortion arising in said main amplifier 4. In a distortion compensation loop the distortion detected in the distortion detection loop is removed from the amplified signal from said main amplifier 4.

Abstract: The object of this invention is to reduce the cost of an amplification device that has a distortion detection loop that uses an amplifier to amplify the signal subject to amplification and detect the distortion arising in said amplifier, and a distortion removal loop that removes the distortion detected by the distortion detection loop from the signal amplified by said amplifier.

Abstract: A feed forward type distortion compensation amplification apparatus, which includes a distortion detection loop and a distortion compensation loop, cancels a first distortion element generated from the distortion detection loop by a second distortion element generated from the distortion compensation loop to generate an output signal, and controls bias levels of the main amplifier and the error amplifier based on a level of the output signal. An adaptive pre-distortion type distortion compensation amplification apparatus includes a detection unit for detecting an input power level, a control unit for storing the input power level and a bias level corresponding thereto and generating the bias level in response to the input power level, and a bias control unit for applying a bias to an amplifier unit in response to the bias level.

Abstract: A feedforward amplifier is provided that divides a signal to be amplified, amplifies one divided signal with a main amplifier, combines the amplified signal and another divided signal to detect distortion components generated in the main amplifier and contained in the amplified signal, amplifies the detected distortion components with an auxiliary amplifier, and combines the amplified distortion components and the amplified signal from the main amplifier to remove those of the distortion components present in a prescribed band from the amplified signal. The feedforward amplifier includes a filter, typically installed ahead of the auxiliary amplifier, that reduces out-of-prescribed-band components contained in the detected distortion components, thereby improving the characteristic of the out-of-prescribed-band noise.

Abstract: A base-station amplifier device for use in amplifying at least one channel to be transmitted from a base station is provide to solve deterioration in radio characteristic caused due to variation of peak signal. The base-station amplifier device comprises: amplitude limiting means for amplitude-limiting a base band signal every said channel; high-frequency modulating means for performing a high-frequency modulation on an output from said amplitude limiting means every said channel; adding means for adding outputs from all of said high-frequency modulating means; amplifying means for amplifying an output from said adding means; and amplitude controlling means for controlling said amplitude limiting means based on characteristic of said amplifying means.

Abstract: In a receiver of the present invention, a local oscillator frequency, used as a basis for a reception unit to demodulate a received signal, is generated by a local oscillator based on a reference frequency, which is generated by a voltage-controlled oscillator whose oscillation frequency is adjusted by a control voltage applied thereto. The control voltage is prescribed by a decoding unit which monitors a reception electric field intensity (RSSi) or an error rate in the reception unit. The control voltage is adjusted in a manner to increase the reception electric field intensity (RSSi) or reduce the error rate. When the local oscillator frequency experiences a large deviation and the signal cannot be received with good reception sensitivity, the decoding unit generates a control voltage in a manner so as to eliminate the deviation and applies the generated control voltage to the voltage-controlled oscillator for automatically adjusting the local oscillator frequency to a level having a reduced deviation.