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    • 1. 发明申请
    • BASEBAND COMPENSATION OF AN OFFSET PHASE LOCKED LOOP
    • 偏移相位锁定环的基带补偿
    • WO2007035738A3
    • 2007-05-10
    • PCT/US2006036490
    • 2006-09-15
    • QUALCOMM INCSEE PUAY HOE ANDREWBALLANTYNE GARY JOHNJAFFEE JAMESSAHOTA GURKANWAL SINGH
    • SEE PUAY HOE ANDREWBALLANTYNE GARY JOHNJAFFEE JAMESSAHOTA GURKANWAL SINGH
    • H04L27/00
    • H04L27/361H03C3/0966H03C3/0983
    • A phase modulator faithfully reproduces higher frequency modulation using an offset phase-locked loop (OPLL) without passing excessive noise through an increased bandwidth of the OPLL. A quadrature modulator modulates information from a baseband signal onto a passband IF signal and, after a limiter strips away amplitude variations, the OPLL reproduces the phase modulation on an RF signal. The OPLL introduces a group delay that does not vary linearly with the modulation frequency and that consequently causes distortion when uncompensated. A baseband filter filters the amplitude of the baseband signal and introduces a complementary group delay that compensates for the OPLL group delay and results in a combined group delay of the baseband filter, quadrature modulator, limiter and OPLL that remains substantially constant as modulation frequency varies. Compensating for the OPLL group delay reduces distortion and the spectral energy at offset frequencies from the carrier frequency of the RF signal.
    • 相位调制器使用偏移锁相环(OPLL)忠实地再现更高的频率调制,而不会通过OPLL的带宽增加而过多的噪声。 正交调制器将信号从基带信号调制到通带IF信号上,并且在限幅器剥离幅度变化之后,OPLL再现RF信号上的相位调制。 OPLL引入了不随调制频率线性变化的群延迟,从而导致无补偿时的失真。 基带滤波器对基带信号的幅度进行滤波,并引入补偿组延迟,补偿OPLL组延迟,并导致基带滤波器,正交调制器,限幅器和OPLL的组合群延迟,其随调制频率变化而保持基本恒定。 补偿OPLL组延迟可以减少偏移频率下的失真和频谱能量与RF信号的载波频率。