Abstract: Systems and methods are provided for generating an amplitude modulation signal to a switchmode power amplifier. A DC to DC switch is configured to receive a DC input voltage and to provide a DC output voltage. A low dropout regulator is configured to provide the amplitude modulation signal according to a modulation control signal received by the low dropout regulator. A control circuit is configured to establish a nominal operating power level for the power amplifier via the amplitude modulation signal and to maintain a minimum voltage difference between the DC output voltage and the low dropout regulator output. A modulator control circuit is configured to provide the modulation control signal to the low dropout regulator. The modulator control circuit provides the transition from a high amplitude to a low amplitude and a transition from the low amplitude to the high amplitude at configurable first and second slopes, respectively.

Abstract: A power amplifier comprises: polar modulator that receives modulated signal including amplitude-modulated component and phase-modulated component, outputs the amplitude-modulated component, superimposes the modulated signal on carrier wave to generate signal output as RF-modulated signal, and delays at least one of the amplitude-modulated component and the RF-modulated signal; first amplitude modulator that receives the amplitude-modulated component, pulse-modulates the amplitude-modulated component to generate signal output as pulse-modulated signal, and amplifies the amplitude-modulated component with the amplitude-modulated component and the pulse-modulated signal as control signals; second amplitude modulator that receives the amplitude-modulated component and the pulse-modulated signal, and amplifies the amplitude-modulated component with the amplitude-modulated component and the pulse-modulated signal as control signals; and first RF amplifier that receives the RF-modulated signal, amplifies the RF-modu

Abstract: A quadrature out-phasing system comprising: a first baseband signal modifier (6) arranged to receive a first baseband signal component (2) and output a first constant envelope RF carrier (12) and a second constant envelope RF carrier (14); and a second baseband signal modifier (8) arranged to receive a second baseband signal component (4) and output a third constant envelope RF carrier (16) and a fourth constant envelope RF carrier (18). The system may further comprise: a first signal combiner (500) arranged to combine the first constant envelope RF carrier (12) and the second constant envelope RF carrier (14), and arranged to output a first RF PWM signal (94); and a second signal combiner (502) arranged to combine the third constant envelope RF carrier (16) and the fourth constant envelope RF carrier (18), and arranged to output a second RF PWM signal (96).

Abstract: An amplitude modulated pulse transmitter designed to operate across a multi MHz range of modulation frequencies. A wire wound rare earth magnet is to be utilized instead of the typical modulation transformer. Additionally, a plurality of electrolytic capacitors are also employed in the transmitter.

Abstract: A transmitter using quadrature modulation includes a rectangular to polar converter for converting data symbols into a polar form, where each polar symbol has a magnitude signal and an angle signal. Digital phase modulation circuitry includes an all digital PLL circuit for generating a phase modulated RF carrier signal responsive to the angle signal frequency control word (FCW) and a carrier frequency FCW. A digitally controlled amplifier for amplifying the phase modulated signal is controlled by a digital amplitude control circuitry for controlling the gain of the digitally controlled amplifier responsive to the magnitude signal.

Abstract: Disclosed is a novel design of a fully integrated UWB transmitter. The transmitter includes a pulse generator, a pulse modulator, and an ultra-wideband drive amplifier. A new low voltage low power pulse generator circuit is disclosed which can be fully integrated in CMOS or BiCMOS process. This circuit includes a squaring stage, an exponential stage, and a second-order derivative stage. Based on this, PPM, BPSK and PAM pulse modulator circuits and system are disclosed. The modulated pulse is symmetrical second-order derivative Gaussian pulses with a bandwidth up to 5 GHz and having sufficient swing for UWB applications. An ultra-wideband driver amplifier is proposed to amplify the modulator output and drive the antenna. For the driver amplifier, common source resistor and inductor shunt feedback with current reuse technique is employed to achieve the ultra-wideband bandwidth, high gain, and providing matching for the antenna simultaneously.

Abstract: A line driver having a non-linear amplifier that is arranged to provide a first output signal, which is an amplified input signal. The line driver also includes an analog linear amplifier providing a second output signal based on the difference between the input signal and the first output signal, placed in parallel with the non-linear amplifier. The line driver also includes a device to combine the first output signal and the second output signal to provide a total output signal to an output line.

Abstract: Amplitude modulator comprising a differential input pair receiving a modulating input signal, and a Gilbert cell multiplying a carrier signal by the modulating input signal; anda second differential pair of transistors receiving the carrier signal, and the output signal of which is added to the output signal of the Gilbert cell.

Abstract: In a high-power transmitter, an input complex signal is multiplied in a complex multiplier by control signals. The output complex signal from the multiplier is converted to a high frequency signal and amplified by a power amplifier for transmission. The amplitude of the input complex signal is detected to access a memory where amplitude and phase correction values are stored. During a read mode of the memory, a set of amplitude and phase correction values is specified by the detected amplitude and supplied to the complex amplifier as the control signals. During a write mode of the memory, a set of amplitude and phase correction values is specified by a delayed version of the detected amplitude and rewritten with a set of new amplitude and phase correction values. The amplified high frequency signal is down-converted to a low frequency complex signal.

Abstract: A modulator or demodulator has a transparent nonlinear dielectric material (crystal), and an optical fiber for coupling light thereinto. RF is coupled into the crystal by a dielectric waveguide which is matched to the crystal. The nonlinear crystal causes the light and RF to interact, to cause products which can be detected at the dielectric waveguide. When used as a modulator or demodulator, the modulated light may be coupled out by a second optical fiber, and or the modulated RF may be coupled out by a second dielectric waveguide. The dielectric waveguide may be transitioned to conventional hollow conductive waveguide.