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    • 3. 发明授权
    • Digital VSB detector with bandpass phase tracker using rader filters, as
for use in an HDTV receiver
    • 数字VSB检测器,带有使用雷达滤波器的带通相位跟踪器,用于HDTV接收机
    • US5548617A
    • 1996-08-20
    • US243480
    • 1994-05-19
    • Chandrakant B. PatelAllen L. Limberg
    • Chandrakant B. PatelAllen L. Limberg
    • H04L27/38H04N5/44H04N5/455H04N5/50H04N7/015H04L27/06H03K1/00
    • H04N5/4401H04L27/3836H04N5/455H04N5/50
    • In a radio receiver for receiving vestigial sideband (VSB) signals including symbol codes descriptive of digital signals, HDTV signals being exemplary of such VSB signals, a tuner provides for selecting one of channels at different locations in a frequency band used for transmitting such VSB signals. The tuner also includes mixers for performing plural conversion of the selected channel to a final intermediate-frequency signal, which is digitized by an analog-to-digital converter. A phase tracker, operative on narrow-bandpass filtered portions of the digitized final intermediate frequency signal centering on its carrier frequency, suppresses an imaginary portion of the final intermediate-frequency signal, arising from multipath distortion or from phase incoherency in local oscillations used during frequency conversion. A digital controlled oscillator in the phase tracker supplies digital descriptions of the carrier wave for the final intermediate-frequency signal to a synchronous detector, which synchronous detector detects the real portion of the digitized final intermediate-frequency signal in accordance with those digital descriptions of the carrier wave pair of all-pass digital filters, which exhibit a constant .pi./2 difference in phase response for the digitized bandpass signals and are designed based on Jacobian elliptic functions as described by C. M. Rader, are used in the phase tracker for generating the real and imaginary portions of the digitized final intermediate-frequency signal.
    • 在用于接收包括描述数字信号的符号代码的残留边带(VSB)信号的无线电接收机中,HDTV信号是这样的VSB信号的示例,调谐器提供用于在用于发送这样的VSB信号的频带中的不同位置处选择一个信道 。 调谐器还包括用于执行所选频道的多个转换到由模数转换器数字化的最终中频信号的混频器。 基于其载波频率的数字化最终中频信号的窄带通滤波部分的相位跟踪器抑制由多径失真引起的最终中频信号的虚部,或者在频率期间使用的局部振荡中的相位不相干性 转换。 相位跟踪器中的数字控制振荡器将最终中频信号的载波的数字描述提供给同步检波器,该同步检测器根据这些数字描述的数字化最终中频信号的实际部分 对于数字化带通信号,其相位响应表现出常数pi / 2的全波数字滤波器的载波对,并且基于由CM Rader描述的雅可比椭圆函数设计,用于相位跟踪器中以产生真实的 和数字化的最终中频信号的虚部。