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公开(公告)号：US07483500B2
公开(公告)日：2009-01-27
申请号：US11399224
申请日：2006-04-06
IPC分类号： H04L27/08
CPC分类号： H04B1/0007 , H03G3/3052 , H04B1/0003 , H04B1/0039 , H04B1/28
摘要： An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined. A wideband sample variance (PW) is also taken from the raw ADC output data over the same period as the time period used for PN. In the presence of out-of-band signal components, PW will be quite different from PN. This difference indicates a desired proportional difference in a control voltage or a gain backoff amount.
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公开(公告)号：US07046749B2
公开(公告)日：2006-05-16
申请号：US09847056
申请日：2001-05-01
IPC分类号： H04L27/08
CPC分类号： H04B1/0007 , H03G3/3052 , H04B1/0003 , H04B1/0039 , H04B1/28
摘要： An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined. A wideband sample variance (PW) is also taken from the raw ADC output data over the same period as the time period used for PN. In the presence of out-of-band signal components, PW will be quite different from PN. This difference indicates a desired proportional difference in a control voltage or a gain backoff amount.
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公开(公告)号：US07653159B2
公开(公告)日：2010-01-26
申请号：US12360464
申请日：2009-01-27
IPC分类号： H04L27/08
CPC分类号： H04B1/0007 , H03G3/3052 , H04B1/0003 , H04B1/0039 , H04B1/28
摘要： An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined. A wideband sample variance (PW) is also taken from the raw ADC output data over the same period as the time period used for PN. In the presence of out-of-band signal components, PW will be quite different from PN. This difference indicates a desired proportional difference in a control voltage or a gain backoff amount.
摘要翻译： 一种在数字接收机中使用的自动增益控制（AGC）电路，其利用具有较宽带宽的主环路滤波器。 从输入数字信号确定预滤波器，宽带方差，并且还确定后滤波器，窄带方差。 然后比较宽带和窄带方差，以确定宽带信号功率是否指示太大而不能允许正常环路操作的方差水平。 通过根据需要将功率电平的这种差异重新应用于滤波器输出，例如通过缩放操作，动态范围的损失被有效地恢复。 在优选实施例中，可调增益输入放大器将中频（IF）信号馈送到模数转换器（ADC）。 然后将数字化的IF信号下变频到基带频率并进行数字滤波。 然后确定数字滤波（窄带）数据的窄带样本方差（PN）。 在与PN使用的时间段相同的周期内，也可以从原始ADC输出数据获取宽带采样方差（PW）。 在存在带外信号分量的情况下，PW将与PN完全不同。 该差异表示控制电压或增益回退量的期望比例差。
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公开(公告)号：US20090135971A1
公开(公告)日：2009-05-28
申请号：US12360464
申请日：2009-01-27
CPC分类号： H04B1/0007 , H03G3/3052 , H04B1/0003 , H04B1/0039 , H04B1/28
摘要： An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined. A wideband sample variance (PW) is also taken from the raw ADC output data over the same period as the time period used for PN. In the presence of out-of-band signal components, PW will be quite different from PN. This difference indicates a desired proportional difference in a control voltage or a gain backoff amount.
摘要翻译： 一种在数字接收机中使用的自动增益控制（AGC）电路，其利用具有较宽带宽的主环路滤波器。 从输入数字信号确定预滤波器，宽带方差，并且还确定后滤波器，窄带方差。 然后比较宽带和窄带方差，以确定宽带信号功率是否指示太大而不能允许正常环路操作的方差水平。 通过根据需要将功率电平的这种差异重新应用于滤波器输出，例如通过缩放操作，动态范围的损失被有效地恢复。 在优选实施例中，可调增益输入放大器将中频（IF）信号馈送到模数转换器（ADC）。 然后将数字化的IF信号下变频到基带频率并进行数字滤波。 然后确定数字滤波（窄带）数据的窄带样本方差（PN）。 在与PN使用的时间段相同的周期内，也可以从原始ADC输出数据获取宽带采样方差（PW）。 在存在带外信号分量的情况下，PW将与PN完全不同。 该差异表示控制电压或增益回退量的期望比例差。
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