75 results about "Gain compression" patented technology

A predistortion circuit for a microwave amplifier and more particularly to predistortion circuit configured as a Doherty amplifier. The predistortion circuit is adapted to be coupled to a downstream Doherty amplifier to precompensate for the gain compression and phase expansion of the downstream Doherty amplifier as the input power level is increased while simultaneously reducing the intermodulation (IM) distortion. In order to provide precompensation, the precompensation circuit is operated at bias level to provide gain expansion and phase compression to cancel out the gain compression and phase expansion of the downstream Doherty amplifier to provide a higher overall linear power added efficiency (PAE).

A Solid State Power Amplifier (SSPA) for powering a single element of a multi-element antenna, the SSPA comprising:

an RF amplifier, having a signal amplifying path that includes preamplifier, driver amplifier and a power output stage;

an Electronic Power Conditioner (EPC) for providing a variable value of DC voltage for powering the power output stage of the RF amplifier;

a control ASIC for receiving an input power signal of the RF amplifier for providing a voltage control signal to the EPC to determine the value of the DC voltage, the control ASIC addressing an EEPROM holding a collection of control words that define output values of a control output signal for varying values of said input power, such that the value of the DC voltage to the power output stage is varied so as to control the gain compression of the RF amplifier for varying values of input power in order to maintain constant amplifier linearity.

The present invention relates generally to semiconductor lasers and laser scanning systems and, more particularly, to schemes for controlling wavelength in semiconductor lasers. According to one embodiment of the present invention, a method of minimizing laser wavelength variations in a semiconductor laser is provided. According to the method, one or more of the laser drive currents is configured to comprise a drive portion and a wavelength recovery portion. The wavelength recovery portion of the drive current comprises a recovery amplitude I_R that is distinct from the drive amplitude I_D and a recovery duration t_R that is less than the drive duration t_D. The recovery amplitude I_R and duration t_R are sufficient to recover carrier density distribution distorted by gain compression effects prior to recovery. Additional embodiments are disclosed and claimed.

The application discloses an adaptive biasing radio frequency power amplifier comprising a biasing circuit and a power level amplifying circuit. The biasing circuit is used for providing dynamic bias voltage for a transistor II in the power level amplifying circuit; the work voltage I is connected to one end of a resistor I; the other end of the resistor I is used as an output end of the biasing circuit; the work voltage II is connected to the anode of a diode I; the cathode of the diode I is connected to the output end of the biasing circuit; the value of the work voltage II makes the diode I in a default critical conduction status. the power level amplifying circuit comprises a transistor I and the transistor II, which adopt common source and common gate structures; the transistor I adopts common source connection and the grid of the transistor I receives radio frequency input signals; the transistor II adopts common grade connection and the drain electrode of the transistor II outputs drain voltage II. The application provides adaptive biasing voltage postponing gain compression and reducing phase distortion caused by non-linear capacity.

The invention discloses a high-linearity broadband stacking low noise amplifier based on a gain compensation technology. The high-linearity broadband stacking low noise amplifier comprises a two-stacking low noise amplification network, an interstage matching network and a two-stacking gain expansion amplification network which are connected in sequence; and a first power supply bias network and a second power supply bias network which are connected with the two-stacking low noise amplification network and the two-stacking gain expansion amplification network. According to the high-linearity broadband stacking low noise amplifier, a serial stacking structure is realized through adoption of two transistors with different sizes and ultra wide band noise and impedance matching are realized through combination of an RLC feedback network; through utilization of the gain compression compensation technology, the gain compression property of the two-stacking low noise amplification network is cancelled within a certain bias range through the two-stacking gain expansion amplification network and a linearity index of the amplifier is improved, so the whole low noise amplifier has good broadband, linearity, low power consumption and low noise amplification capability; and moreover, the low breakdown voltage property of an integrated circuit technology is avoided and the stability and reliability of a circuit are improved.

Circuits and methods for controlling power amplifiers. In some embodiments, a power amplification system can include a first amplification stage configured to operate with a first bias signal, and a second amplification stage configured operate with a second bias signal. The power amplification system can further include a control circuit coupled to the first amplification stage and the second amplification stage. The control circuit can be configured to generate the first bias signal based on the second bias signal. Such a first bias signal can result in the first stage having a gain profile that compensates for either or both of a gain expansion and gain compression of the second amplification stage.

The invention provides a high-linearity envelope tracking power amplifier with a self-adaptive biased node, comprising a drive common-source common gate and a common-gate self-biased circuit thereof, an output common-source common gate and a common-gate self-biased circuit thereof, and a two-stage common-source self-adaptive biased circuit. Compared to the traditional fixed-gate biased envelope tracking power amplifier and linear power amplifier, the invention can offset the gain variation which is generated by the variable power voltage of an envelope tracking power amplifier, increase the gain compression features of A and B type power amplifiers, eliminate some AM-AM distortion and greatly improve the linearity and stability of the whole envelope tracking power amplifier.

Apparatus and a corresponding method for predistorting an input signal applied to a radio frequency (RF) power amplifier, to compensate for amplifier distortion at high powers. The RF amplifier input and output signals are continuously monitored and difference signals are generated in an RF phase discriminator. The difference signals are converted to digital form and stored in a lookup table in the form of running averages of an RF amplifier gain compression value and an RF amplifier output phase value for each observed RF input power value. A predistorter module retrieves these values and predistorts the RF amplifier input by way of compensation.

The invention relates to the technical field of communications, in particular relates to a radio-frequency power amplifier which comprises a linearity compensation circuit and an amplifier, wherein the linearity compensation circuit and the amplifier are connected in parallel; the linearity compensation circuit comprises a primary radio-frequency amplifier transistor and a bias circuit enabling the amplifier transistor to generate gain compression; and the radio-frequency power amplifier is biased at a class AB state. According to the invention, the circuit generating linearized compensation enables the bias current of the primary radio-frequency amplifier transistor to increase along with the increment of input power through the adaptive adjustment of the bias circuit; the gain of the radio-frequency amplifier transistor is increased in the case of relatively higher power input so as to generate gain expansion; and by connecting the primary radio-frequency amplifier transistor with the other level of amplifier in parallel, the generated gain expansion can be used for compensating the gain compression of the level of amplifier so as to improve the linearity of the power amplifier.

The invention discloses a radio-frequency power amplifier circuit with adjustable predistortion function, comprising a transistor in emitter follower structure; wherein the base electrode of the transistor is connected with the input terminal of the amplifier circuit, the emitter of the transistor is connected with the output terminal of the amplifier circuit by virtue of an output matching network, an RC parallel negative feedback network is connected between the base electrode of the transistor and the collector electrode of the transistor, a first RL series negative feedback network is connected between the collector electrode and an external adjustable bias voltage, and a second RL series negative feedback network is connected between the emitter of the transistor and the ground. Predistortion circuit can be caused to have better accuracy, gain compression and positive phase deviation produced by power amplifier post-stage circuit can be compensated, and linearity thereof can be improved.

Because of associated disadvantages of narrow-band off-chip radio-frequency (RF) filtering, a mixer-first receiver front-end designed to tolerate blockers with minimal gain compression and noise factor degradation is disclosed. The mixer-first receiver front-end includes two separate downconversion paths that help to minimize added noise and voltage gain prior to baseband filtering, which are critical factors in eliminating narrow-band off-chip RF filtering.

The invention discloses a self-adaptive linearization radio frequency biasing circuit which comprises a linearization biasing circuit and a radio frequency amplifier unit circuit. The linearization biasing circuit is connected with the radio frequency amplifier unit circuit through a self-adaptive linear compensation circuit; the linearization biasing circuit comprises a heterojunction bipolar transistor HBT2, a heterojunction bipolar transistor HBT3, a heterojunction bipolar transistor HBT4, a resistor R3, a resistor R4, a resistor R5 and a capacitor C2. The collector electrode of the heterojunction bipolar transistor HBT4 is connected with the port of the linearized bias circuit; self-adaptive linear compensation is achieved through feedback of the heterojunction bipolar transistor HBT4of the self-adaptive linear compensation circuit, the heterojunction bipolar transistor HBT0 can select a bias state according to the magnitude of output power, and the linearity is improved while theefficiency is considered by the power amplifier; the gain compression and phase distortion characteristics of the HBT can be effectively improved; the MMIC power amplifier is simple in structure, small in size, low in cost and suitable for design of the MMIC power amplifier.

The invention discloses a biasing circuit for a radio frequency power amplifier, wherein the biasing circuit comprises an input and amplification module which is used for receiving an input radio frequency signal, amplifying the radio frequency signal and then providing the amplified radio frequency signal to an output end, and comprises a radio frequency power tube QRF for amplifying a radio frequency signal; a first rectification path module, which is used for compensating for gain compression in medium power; a second rectification path module which is used for compensating for gain compression in high power, wherein the first rectification path module comprises a transistor Q3, and the second rectification path module comprises a transistor Q1 shared by the first rectification path module; a voltage stabilization and current regulation module, which is used for keeping the conducting state of the transistor Q1 and adjusting the proportion of current distributed to the transistor Q1 and the transistor Q3; a radio frequency choke module which is used for blocking leakage of radio frequency signals; and a temperature compensation module that is used for inhibiting the increase of the collector current of the transistor Q1 caused by temperature rise.

The invention provides an amplifier for providing adaptive operation of an auditory prosthesis. The amplifier receives an input signal and produces an output signal, and comprises a gain control. Estimates of the current noise floor value of the input signal are obtained, and in response to a change in the current estimated noise floor value, the gain control alters the amount of gain applied to the input signal. Further, in response to the change in the current estimated noise floor value, the gain control alters a gain compression ratio of the amplifier across the dynamic range of the amplifier. The present invention allows for adaptive operation of the amplifier responsive to varying noise floor levels, while maintaining desired gain characteristics of the amplifier across a range of input signal levels.

The invention relates to a 5G power amplifier testing device and method. The device comprises a vector network, a device under test (DUT), and a testing accessory, and is characterized in that the device also comprises a power amplifier integrated spread spectrum module at the output end and a power amplifier integrated spread spectrum module at the receiving end of the vector network; the power amplifier integrated spread spectrum module at the output end comprises a vector network output end spread spectrum module, a power amplifier and a double-shaped coupler which are electrically connected in sequence; the power amplifier integrated spread spectrum module at the receiving end comprises a vector network receiving end double-shaped coupler and a spread spectrum module which are electrically connected in sequence; and each double-shaped coupler is also electrically connected with the vector network through a respective down converter. The method adopts the spread spectrum module to perform index measurement after vector network spread spectrum, including power gain, power gain flatness, linear power gain, linear power flatness, 1dB gain compression output power, clutter suppression degree, input voltage standing-wave ratio, output voltage standing-wave ratio and power additional efficiency. According to the device and the method thereof, the test investment cost of the 5G power amplifier is greatly reduced, and meanwhile, the risks of prohibition and technology blocking are effectively avoided.

The invention provides a gain compression and interception waveform sampling method for a transient short optical pulse semiconductor optical amplifier. , the sequence pulse amplitudes are arranged according to a fixed attenuation ratio. Then, according to the pulse sequence timing determined by the length of the passive optical fiber loop, the pulse is intercepted by the semiconductor optical amplifier. The intercepted pulse waveform is sent to a PIN photocell with a bandwidth of 100 megabytes, and then the data acquisition card is used to measure the output pulse amplitude of the PIN photocell to obtain the energy envelope of the intercepted pulse, and then combine the passive fiber ring pulse to copy. The original transient short optical pulse waveform is reversed by the replica amplitude variation law of the generator. The method provided by the invention adopts a simple system structure, low equipment requirements, easy debugging and integration, and can be used as an effective means for measuring transient short light pulses.