New partial response signaling systems and methods for high spectral efficiency communications are described. In a first implementation, a communication system includes a partial response signaling transmitter and a nonlinear satellite transponder. The partial response signaling transmitter includes a partial response transmit filter configured to convert complex-valued data symbols to a transmit signal using a partial response pulse shaping function; and a modulator configured to modulate the transmit signal onto a carrier wave. The transponder receives and non-linearly amplifies the modulated transmit signal for broadcast to receivers. In a second implementation, a receiver includes circuitry for downconverting a received input signal; a partial response filter with a partial response impulse function for filtering the downconverted signal; circuitry for downsampling the partial response filtered signal; circuitry for equalizing the downsampled signal; and a linear and non-linear interference cancellation module including circuitry for removing linear and non-linear ISI in the input signal.

Present application provides embodiments of a transmitter and an interference cancellation method. The transmitter includes: a first digital predistorter (DPD), a power amplifier (PA), and a first processor located on a feedback channel of the transmitter and separately connected to the PA and the first DPD. The first processor performs, according to a feedback cancellation signal, interference cancellation on a signal of the feedback channel, to acquire a first mixed signal, and sends the first mixed signal to the first DPD. The first DPD is configured to perform linear predistortion processing according to a first baseband signal on a first transmit channel and the first mixed signal, to generate a first predistortion signal. The PA is configured to amplify and then transmit a to-be-transmitted signal using an antenna. The to-be-transmitted signal is the first predistortion signal or a signal obtained according to the first predistortion signal.

One example discloses An equalizer, including: a first transistor and a second transistor both coupled to a first differential input (IP); a third transistor and a fourth transistor both coupled to a second differential input (IN); a first impedance (Z.sub.E1) coupled between the second transistor and the third transistor; a second impedance (Z.sub.E2) coupled between the first transistor and the fourth transistor; a first load resistance (R.sub.L1) coupled to a first supply node; a second load resistance (R.sub.L2) coupled to the first supply node; a current steering circuit coupled between the first, second, third and fourth transistors and the first and second load resistances; and a controller; wherein the controller is configured to adjust the current steering circuit to route a first percentage of an amplification current through the first impedance (Z.sub.E1) and a second percentage of the amplification current through the second impedance (Z.sub.E2).

Systems and methods for transceiver communication are discussed herein. A filter module may be configured to filter each carrier signal of a multicarrier transmit signal with a different bandpass filter, each bandpass filter configured to filter a different frequency band. A carrier control module may be configured to control the plurality of bandpass filters of the filter module using a carrier selection signal to enable or disable each bandpass filter, thereby coupling carrier signals of the multicarrier transmit signal to a first set of bandpass filters and decoupling a second set of bandpass filters. Filtering the carrier signals of the multicarrier transmit signal is performed by the first set of bandpass filters while the decoupling of the second set of bandpass filters limits energy in the respective frequency band. An antenna may be configured to transmit the filtered multicarrier transmit signal.

An Open Radio Access Network Radio Unit (O-RU) including a Radio Frequency (RF) unit and a baseband unit, wherein: the baseband unit includes two or more digital signal processing units; the two or more digital signal processing units are configured to execute digital signal processing with respectively defined higher-level units; and the baseband unit is configured so as to be able to make some of the two or more digital signal processing units execute the digital signal processing and so as to be able to switch between the digital signal processing units that are made to execute the digital signal processing.

Disclosed is a receiver that includes a pre-amplifier circuit and an amplifier circuit. The pre-amplifier circuit includes first and second input terminals that receive signals from a transmitter; first and second output terminals that output signals to the amplifier circuit; a first resistor having a first terminal coupled to the first input terminal, and a second terminal coupled to a first node; a second resistor having a first terminal coupled to the second input terminal, and a second terminal coupled to the first node; a third resistor having a first terminal coupled to the first output terminal, and a second terminal coupled to a second node; a fourth resistor having a first terminal coupled to the second output terminal, and a second terminal coupled to the second node; and a switch having a first terminal coupled to the first node, and a second terminal coupled to the second node.

Intra-symbol voltage modulation in a wireless communication circuit is disclosed. In a wireless communication circuit, a power amplifier circuit is configured to amplify a radio frequency (RF) signal based on a modulated voltage that tracks a time-variant input power of the RF signal. Herein, intra-symbol voltage modulation means that the modulated voltage can be adapted within a voltage modulation interval(s), such as an orthogonal frequency division multiplexing (OFDM) symbol duration. In embodiments disclosed herein, the voltage modulation interval(s) is divided into multiple voltage modulation subintervals and a respective voltage target is determined for each of the voltage modulation subintervals. Accordingly, the modulated voltage can be adapted in each of the voltage modulation subintervals according to the respective voltage target. By performing intra-symbol voltage modulation during the voltage modulation interval(s), the power amplifier circuit can operate with higher efficiency and prevent distortion (e.g., amplitude clipping) when amplifying the RF signal.

Systems and methods for pulse shaping of baseband signals in a communication network using Electro Quasistatic signal is disclosed. The system up-samples baseband symbols in digital domain for generating an up-sampled baseband symbols. Further, the system pulse shapes the up sampled baseband symbols in the digital domain to generate pulse shaped symbols to be transmitted as a bandlimited waveform based on spectral mask requirements. The system up-converts a frequency of the pulse shaped symbols in digital domain to a desired frequency band for generating a frequency up converted pulse shaped waveform based on a sampling frequency and a symbol rate. The system further generates a reference analog signal (St) by converting the frequency up converted pulse shaped waveform in digital domain to analog domain. Furthermore, the system communicates the generated reference analog signal to a receiver system using a human body.

An electronic device includes a processor, a modulator, and a power amplifier. The processor receives a baseband signal and executes a first ET shaping function on the baseband signal. The modulator receives the baseband signal, detects the magnitude of the baseband signal, and outputs the first voltage according to the magnitude of the baseband signal. The power amplifier outputs an amplified signal based on the first voltage. The first ET shaping function enables the relationship between the baseband signal and the first voltage to be Vpa=a|X|.sup.2+b. X is the baseband signal, Vpa is the first voltage, and a and b are constants. The look-up table records the relation curve between the power of the amplified signal and the first voltage when the second ET shaping function is used for envelope tracking.

A frequency and power modulation radio frequency (RF) generator includes a first frequency and power modulation RF generator including a signal generator configured to generate an RF signal, an amplifier configured to amplify power of the RF signal from the signal generator, and a phase controlled power correction (PCPC) circuit configured to control a phase of the RF signal amplified by the amplifier. The signal generator, the amplifier, and the PCPC circuit are controlled to perform multi-level pulsing and frequency modulation on the RF signal, thereby supplying RF power of the RF signal to a chamber. The multi-level pulsing has pulse forms with different power levels.