TRANSMITTER AND ITS CONTROL METHOD

摘要

According to an embodiment, a digital transmitter (1) includes an amplitude modulation amplitude signal generation unit (132) that generates a function f(A(t)) of an amplitude signal A(t) as an amplitude modulation amplitude signal A′(t), an amplitude modulation phase signal generation unit (133) that calculates “cos−1{A(t)/f(A(t))}” as a phase θ1(t) and generates amplitude modulation phase signals P1(t) and P2(t), an individual digital transmission unit (11) that generates an amplified RF-pulse signal based on the signals A′(t) and P1(t), an individual digital transmission unit (12) that generates an amplified RF-pulse signal based on the signals A′(t) and P2(t), and an RF-synthesizer (16) that combines outputs of the individual digital transmission units (11, 12) with each other.

主权项

1. A transmitter comprising:
quadrature converter that performs a quadrature modulation on a digital signal and thereby outputs a quadrature radio signal; amplitude modulation amplitude signal generation unit that generates a first predetermined function of an amplitude signal indicating an amplitude of the quadrature radio signal as an amplitude modulation amplitude signal; amplitude modulation phase signal generation unit that calculates an inverse trigonometric function of a value according to the first predetermined function as a first phase and generates first and second amplitude modulation phase signals having phases shifted on positive and negative sides, respectively, by an amount corresponding to the first phase from a phase signal indicating a phase of the quadrature radio signal; first pulse phase signal generator that generates a first pulse phase signal having a pulse waveform based on the first amplitude modulation phase signal; first ΔΣ-modulator that performs a ΔΣ-modulation on the amplitude modulation amplitude signal in synchronization with the first pulse phase signal; first mixer that generates a first RF-pulse signal by mixing an output signal of the first ΔΣ-modulator with the first pulse phase signal; a first switching amplifier that amplifies the first RF-pulse signal; second pulse phase signal generator that generates second pulse phase signal having a pulse waveform based on the second amplitude modulation phase signal; second ΔΣ-modulator that performs a ΔΣ-modulation on the amplitude modulation amplitude signal in synchronization with the second pulse phase signal; second mixer that generates a second RF-pulse signal by mixing an output signal of the second ΔΣ-modulator with the second pulse phase signal; a second switching amplifier that amplifies the second RF-pulse signal; and synthesizer that combines outputs of the first and second switching amplifiers with each other.