Patent ID: 9014300
Filing Date: 2015-04-21
Classification: H04L

Abstract:
1. A quadrature amplitude modulation (QAM) transmitter, comprising: a baseband circuit to generate an in-phase (I) signal and a quadrature (Q) signal; a first circuit, having inputs to receive the I signal and a first clock signal, to generate a first pulse-width modulated (PWM) signal; a second circuit, having inputs to receive an inverted I signal and the first clock signal, to generate a second PWM signal; a third circuit, having inputs to receive the Q signal and a second clock signal, to generate a third PWM signal; a fourth circuit, having inputs to receive an inverted Q signal and the second clock signal, to generate a fourth PWM signal; a first signal combiner, coupled to the first and second circuits, to generate an output I signal in response to one or more even-ordered harmonics of the first and second PWM signals, wherein the first signal combiner is to suppress odd order harmonics from the output I signal by subtracting the second PWM signal from the first PWM signal; a second signal combiner, coupled to the third and fourth circuits, to generate an output Q signal in response to one or more even-ordered harmonics of the third and fourth PWM signals, wherein the second signal combiner is to suppress odd order harmonics from the output Q signal by subtracting the fourth PWM signal from the third PWM signal; and a summing node to generate a QAM output signal in response to a summing of the output I signal and the output Q signal, wherein a frequency of the QAM output signal approximately equals a number N times a frequency of the first clock signal, wherein N is an even integer greater than 2.