Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by changing the amplitude of the legacy data symbols. In exemplary embodiments of the present invention, additional data capacity can be achieved for a COFDM signal which is completely backwards compatible with existing legacy satellite broadcast communications systems. In exemplary embodiments of the present invention, additional information can be overlaid on a legacy COFDM signal by applying an amplitude offset to the legacy symbols. In exemplary embodiments of the present invention, special receiver processing can be implemented to extract this additional information, which can include performing channel equalization across frequency bins to isolate the amplitude modulated overlay signal. For example, at each FFT symbol time, average power across neighboring active data bins can be used to determine the localized power at the corresponding FFT bins, and a channel inversion can then, for example, be performed on the data bins to restore, as best as possible, the original transmitted symbol amplitude.

Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by changing the amplitude of the legacy data symbols. In exemplary embodiments of the present invention, additional data capacity can be achieved for a COFDM signal which is completely backwards compatible with existing legacy satellite broadcast communications systems. In exemplary embodiments of the present invention, additional information can be overlaid on a legacy COFDM signal by applying an amplitude offset to the legacy symbols. In exemplary embodiments of the present invention, special receiver processing can be implemented to extract this additional information, which can include performing channel equalization across frequency bins to isolate the amplitude modulated overlay signal. For example, at each FFT symbol time, average power across neighboring active data bins can be used to determine the localized power at the corresponding FFT bins, and a channel inversion can then, for example, be performed on the data bins to restore, as best as possible, the original transmitted symbol amplitude.

A method of encoding video data comprising: generating coefficients based on digital sample values of the video data; determining a spectral efficiency for a channel; determining a value n based on the spectral efficiency of the channel; generating coefficient vectors, wherein each of the coefficient vectors includes n of the coefficients; determining an amplitude value for a coefficient vector based on a mapping pattern, wherein for each respective allowed coefficient vector in a plurality of allowed coefficient vectors: the mapping pattern maps the respective allowed coefficient vector to a respective amplitude value in a plurality of amplitude values, and the respective amplitude value is adjacent in an n-dimensional space to at least one other amplitude value in the plurality of amplitude values that is adjacent to the respective amplitude value in a monotonic number line of the amplitude values, and modulating an analog signal based on the amplitude values.

A method of encoding video data comprising: generating coefficients based on digital sample values of the video data; determining a spectral efficiency for a channel; determining a value n based on the spectral efficiency of the channel; generating coefficient vectors, wherein each of the coefficient vectors includes n of the coefficients; determining an amplitude value for a coefficient vector based on a mapping pattern, wherein for each respective allowed coefficient vector in a plurality of allowed coefficient vectors: the mapping pattern maps the respective allowed coefficient vector to a respective amplitude value in a plurality of amplitude values, and the respective amplitude value is adjacent in an n-dimensional space to at least one other amplitude value in the plurality of amplitude values that is adjacent to the respective amplitude value in a monotonic number line of the amplitude values, and modulating an analog signal based on the amplitude values.

An integrated circuit (IC) includes a serial-to-parallel converter configured to receive a serial input signal to provide one or more parallel output signals. The serial input signal is an M-level Pulse-Amplitude Modulated (PAM) signal, wherein M is a positive integer. The serial-to-parallel converter includes a data converter configured to receive the serial input signal and provide a data converter output signal. The data converter output signal represents information of the serial input signal with N1 bits, and N1 is a positive integer. An encoder is configured to encode the data converter output signal to provide encoder output signal with N2 bits, wherein N2 is a positive integer less than half of N1. One or more sub-deserializers are configured to receive the encoder output signal and generate the one or more parallel output signals.

A digital quadrature modulator holds local oscillator circuitry configured to provide local oscillator signals, and local oscillator polarity logic circuitry configured to select an In-phase and a Quadrature local oscillator signal according to a sign bit of an In-phase control word and a sign bit of a Quadrature control word, respectively. The modulator holds a number of local oscillator control logic circuits, each configured to generate a conditioned signal by gating one or both of the selected local oscillator signals according to values of the In-phase control word and/or values of the Quadrature control word. The modulator has one or more sets of switched-capacitor units, where each unit has an output provided by an output capacitor, and where a signal at the input side of the output capacitor is controlled by a conditioned signal. The outputs of at least two of the switched-capacitor units are combined in a common node.

A digital quadrature modulator holds local oscillator circuitry configured to provide local oscillator signals, and local oscillator polarity logic circuitry configured to select an In-phase and a Quadrature local oscillator signal according to a sign bit of an In-phase control word and a sign bit of a Quadrature control word, respectively. The modulator holds a number of local oscillator control logic circuits, each configured to generate a conditioned signal by gating one or both of the selected local oscillator signals according to values of the In-phase control word and/or values of the Quadrature control word. The modulator has one or more sets of switched-capacitor units, where each unit has an output provided by an output capacitor, and where a signal at the input side of the output capacitor is controlled by a conditioned signal. The outputs of at least two of the switched-capacitor units are combined in a common node.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.

One embodiment provides a broadband signal source. The broadband signal source includes a number, n, signal paths and a combiner circuitry. Each signal path, i, includes a programmable phase shifter circuitry, an amplifier circuitry and a harmonic generation circuitry. The programmable phase shifter circuitry is configured to phase shift a path input signal by a respective phase angle, θ.sub.i. The path input signal corresponds to a source input signal having a fundamental frequency, f, and an input signal bandwidth. The amplifier circuitry is configured to amplify the phase shifted path input signal. The harmonic generation circuitry is configured to generate a path output signal including a plurality of harmonics of the amplified phase shifted path input signal. The combiner circuitry is configured to combine the number, n, path output signals to produce a broadband output signal having an output signal center frequency greater than the input signal fundamental frequency and an output signal bandwidth greater than the input signal bandwidth.