公开(公告)号：US08032576B2

公开(公告)日：2011-10-04

申请号：US11859863

申请日：2007-09-24

申请人： Takamitsu Hafuka ,  Masato Tanaka ,  Hiroji Akahori

发明人： Takamitsu Hafuka ,  Masato Tanaka ,  Hiroji Akahori

IPC分类号： G06F17/14

CPC分类号： G06F17/142

摘要： A fast Fourier transform circuit includes a computation component, an extraction component and a setting component. The extraction component, at each step of the computation, extracts, from computation result data points calculated by the computation component, data in a pre-specified range with a number of bits the same as a predetermined number of bits, which is an effective range for a butterfly computations. The setting component sets the data points of the predetermined number of bits which have been extracted by the extraction component to serve as input data when butterfly computations of a next step are to be performed by the computation component.

摘要翻译： 快速傅里叶变换电路包括计算部件，提取部件和设定部件。 在计算的每个步骤中，提取组件从计算组件计算的计算结果数据点中提取具有与预定位数相同的位数的预定范围内的数据，该预定位数是有效范围 用于蝴蝶计算。 当由计算部件执行下一步骤的蝶式计算时，设定部件将由提取部件提取的预定位数的数据点设定为输入数据。

公开(公告)号：US07983360B2

公开(公告)日：2011-07-19

申请号：US12955603

申请日：2010-11-29

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H03K9/00 ,  H04L27/00

CPC分类号： H04L27/2647 ,  H03G3/3052 ,  H03G3/3078 ,  H04L25/03159 ,  H04L27/2657

摘要： A radiofrequency signal is converted to an intermediate frequency signal by a tuner, which is amplified by a variable gain amplifier. The so-amplified signal is converted into a digital signal by an ADC, which is supplied to an FFT, where it is separated into signals set every carrier, followed by being supplied to equalizers different in characteristic. The digital signal outputted from the ADC is further supplied to a level converting circuit from which a control signal is generated. The control signal is supplied to a DAC and a Doppler frequency detector. The DAC generates a gain control signal and supplies the same to the variable gain amplifier. The Doppler frequency detector outputs a frequency component of the control signal as a Doppler detection signal. The Doppler detection signal is compared with a threshold value by a comparator. A selector selects one of signals outputted from the equalizers, in accordance with a select signal indicative of the result of comparison.

摘要翻译： 射频信号由调谐器转换成中频信号，该调谐器由可变增益放大器放大。 被放大的信号被ADC转换成数字信号，ADC被提供给FFT，其中被分离成每个载波设置的信号，随后被提供给不同特性的均衡器。 从ADC输出的数字信号进一步提供给产生控制信号的电平转换电路。 控制信号被提供给DAC和多普勒频率检测器。 DAC产生增益控制信号并将其提供给可变增益放大器。 多普勒频率检测器输出控制信号的频率分量作为多普勒检测信号。 通过比较器将多普勒检测信号与阈值进行比较。 选择器根据表示比较结果的选择信号来选择从均衡器输出的信号之一。

公开(公告)号：US07978775B2

公开(公告)日：2011-07-12

申请号：US11923811

申请日：2007-10-25

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H04K1/10 ,  H04L27/28

CPC分类号： H04L27/2657 ,  H04L5/0048 ,  H04L27/2675

摘要： A frequency offset detector is provided which is adaptable to a great frequency offset of one or more carrier waves in an OFDM signal. The frequency offset detector comprises a multiplication circuit which multiplies, by a pseudorandom number bit sequence, a reception signal generated by Fourier transformation of an OFDM modulated signal wherein pilot symbols are dispersed and arranged in accordance with four kinds of patterns and periodically transmitted. Four arithmetic circuits extract the pilot symbols corresponding to the respective patterns from a result of the multiplication by the multiplication circuit for each of the four kinds of patterns and calculate the sum of phase differences among the extracted pilot symbols to output an absolute value. A detection circuit detects a frequency offset on the basis of a maximum value of the absolute values calculated by the four arithmetic circuits. A complex sinusoidal wave is generated on the basis of the detected frequency offset, and the frequency of an input signal is converted thereby, such that the offset of the reception signal can be corrected.

摘要翻译： 提供一种频偏检测器，其能够适应OFDM信号中的一个或多个载波的大的频率偏移。 频率偏移检测器包括乘法电路，该乘法电路通过伪随机数位序列乘以通过OFDM调制信号的傅里叶变换产生的接收信号，其中导频符号根据四种模式被分散和布置并周期性地发送。 四个运算电路从四种模式中的每一种的乘法电路的乘法结果中提取与各个模式相对应的导频符号，并计算提取的导频符号之间的相位差之和以输出绝对值。 检测电路基于由四个运算电路计算的绝对值的最大值来检测频率偏移。 基于检测到的频率偏移产生复杂的正弦波，并且由此转换输入信号的频率，使得可以校正接收信号的偏移。

公开(公告)号：US07482958B2

公开(公告)日：2009-01-27

申请号：US11874293

申请日：2007-10-18

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H03M1/00

CPC分类号： H03M1/185

摘要： The present invention provides an OFDM receiver having a level control section comprising comparators which respectively compare a first signal outputted from an ADC with threshold values, counters which respectively count the frequencies with which the level of the first signal exceeds the threshold values, based on second and third signals corresponding to the results of comparison by the comparators, a moving average unit which calculates an average value of the level of the first signal lying in a predetermined period, based on fourth and fifth signals corresponding to the frequencies counted by the these counters, and a DAC which generates a gain control signal for controlling an AMP in such a manner that the average level of the first signal outputted from the ADC becomes a predetermined value, according to a sixth signal calculated by the moving average unit.

摘要翻译： 本发明提供了一种OFDM接收机，其具有电平控制部分，该电平控制部分包括比较器，它们分别将从ADC输出的第一信号与阈值进行比较，计数器分别对第一信号的电平超过阈值的频率进行计数，基于第二 以及与比较器的比较结果对应的第三信号，基于与由这些计数器计数的频率相对应的第四和第五信号计算在预定时段内的第一信号的电平的平均值的移动平均单元 以及DAC，其根据由移动平均单元计算出的第六信号，生成用于控制AMP的增益控制信号，使得从ADC输出的第一信号的平均电平变为预定值。

公开(公告)号：US20080101216A1

公开(公告)日：2008-05-01

申请号：US11926327

申请日：2007-10-29

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H04J11/00 ,  H03H7/30

CPC分类号： H04L25/0212 ,  H04L25/0224 ,  H04L25/03159 ,  H04L27/2647

摘要： An equalizer equalizes a received orthogonal frequency division multiplex (OFDM) signal which includes periodic pilot symbols. The equalizer includes a channel estimation unit which estimates a frequency response the received OFDM signal, and an equalization circuit which equalizes the received OFDM signal in accordance with the frequency response estimated by the channel estimation circuit so as to output a resultant equalized OFDM signal. The channel estimation circuit determines complex gain amounts of respective propagation channels of the OFDM signal based on the pilot symbols, applies the complex gain amounts to a window function circuit which passes given complex gain amounts among the complex gain amounts which are contained within a predetermined time region window, and computes the frequency response based on the given complex gain amounts which are contained within the predetermined time region window.

摘要翻译： 均衡器对包括周期性导频符号的接收正交频分复用（OFDM）信号进行均衡。 均衡器包括：估计接收到的OFDM信号的频率响应的信道估计单元;以及根据由信道估计电路估计的频率响应来均衡接收的OFDM信号的均衡电路，以输出合成的均衡OFDM信号。 信道估计电路基于导频符号确定OFDM信号的各个传播信道的复数增益量，将复增益量应用于通过给定复数增益量的窗函数电路，该复增益量包含在预定时间内 并且基于包含在预定时间窗口内的给定复数增益量来计算频率响应。

公开(公告)号：US08045630B2

公开(公告)日：2011-10-25

申请号：US11905007

申请日：2007-09-27

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H04L27/28 ,  H04J11/00

CPC分类号： H04L27/2647 ,  H04H40/27 ,  H04L5/0007 ,  H04L5/0048 ,  H04L27/2613

摘要： A detector of patterns corresponding to pilot symbols is capable of detecting patterns of SP symbols promptly without using a TMCC signal. The SP location detector includes a multiplier which multiplies received signals generated by demodulating OFDM modulation signals in which pilot symbols are dispersively disposed in accordance with four types of patterns and which are transmitted periodically by a pseudo-random number bit sequence, four arithmetic circuits which are respectively provided corresponding to the four types of patterns and which respectively extract pilot symbols corresponding to respective patterns from results of multiplication by the multiplier and calculate sums of phase differences between the extracted pilot symbols, followed by outputting absolute values thereof, and a pattern detection circuit which detects the corresponding arithmetic circuit maximum in the calculated absolute value from within the four arithmetic circuits.

摘要翻译： 对应于导频符号的图案的检测器能够在不使用TMCC信号的情况下及时检测SP符号的图案。 SP位置检测器包括乘法器，其乘以通过解调其中导频符号根据四种类型的模式而分散布置并且由伪随机数比特序列周期性地传输的OFDM调制信号而生成的接收信号，四个运算电路 分别对应于四种类型的图案，并且分别从乘法器的乘法结果中分别提取与各个图案相对应的导频符号，并且计算提取的导频符号之间的相位差之和，然后输出其绝对值，以及模式检测电路 其在四个算术电路内检测计算出的绝对值中相应的算术电路最大值。

公开(公告)号：US20080215656A1

公开(公告)日：2008-09-04

申请号：US11859863

申请日：2007-09-24

申请人： Takamitsu Hafuka ,  Masato Tanaka ,  Hiroji Akahori

发明人： Takamitsu Hafuka ,  Masato Tanaka ,  Hiroji Akahori

IPC分类号： G06F17/14

CPC分类号： G06F17/142

摘要： A fast Fourier transform circuit includes a computation component, an extraction component and a setting component. The extraction component, at each step of the computation, extracts, from computation result data points calculated by the computation component, data in a pre-specified range with a number of bits the same as a predetermined number of bits, which is an effective range for a butterfly computations. The setting component sets the data points of the predetermined number of bits which have been extracted by the extraction component to serve as input data when butterfly computations of a next step are to be performed by the computation component.

摘要翻译： 快速傅里叶变换电路包括计算部件，提取部件和设定部件。 在计算的每个步骤中，提取组件从计算组件计算的计算结果数据点中提取具有与预定位数相同的位数的预定范围内的数据，该预定位数是有效范围 用于蝴蝶计算。 当由计算部件执行下一步骤的蝶式计算时，设定部件将由提取部件提取的预定位数的数据点设定为输入数据。

公开(公告)号：US07856066B2

公开(公告)日：2010-12-21

申请号：US11923212

申请日：2007-10-24

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H04K1/10 ,  H04L27/28

CPC分类号： H04L27/2647 ,  H03G3/3052 ,  H03G3/3078 ,  H04L25/03159 ,  H04L27/2657

摘要： A radiofrequency signal is converted to an intermediate frequency signal by a tuner, which is amplified by a variable gain amplifier. The so-amplified signal is converted into a digital signal by an ADC, which is supplied to an FFT, where it is separated into signals set every carrier, followed by being supplied to equalizers different in characteristic. The digital signal outputted from the ADC is further supplied to a level converting circuit from which a control signal is generated. The control signal is supplied to a DAC and a Doppler frequency detector. The DAC generates a gain control signal and supplies the same to the variable gain amplifier. The Doppler frequency detector outputs a frequency component of the control signal as a Doppler detection signal. The Doppler detection signal is compared with a threshold value by a comparator. A selector selects one of signals outputted from the equalizers, in accordance with a select signal indicative of the result of comparison.

摘要翻译： 射频信号由调谐器转换成中频信号，该调谐器由可变增益放大器放大。 被放大的信号被ADC转换成数字信号，ADC被提供给FFT，其中被分离成每个载波设置的信号，随后被提供给不同特性的均衡器。 从ADC输出的数字信号进一步提供给产生控制信号的电平转换电路。 控制信号被提供给DAC和多普勒频率检测器。 DAC产生增益控制信号并将其提供给可变增益放大器。 多普勒频率检测器输出控制信号的频率分量作为多普勒检测信号。 通过比较器将多普勒检测信号与阈值进行比较。 选择器根据表示比较结果的选择信号来选择从均衡器输出的信号之一。

公开(公告)号：US20080095255A1

公开(公告)日：2008-04-24

申请号：US11905007

申请日：2007-09-27

申请人： Masato Tanaka ,  Hiroji Akahori

发明人： Masato Tanaka ,  Hiroji Akahori

IPC分类号： H04B7/10

CPC分类号： H04L27/2647 ,  H04H40/27 ,  H04L5/0007 ,  H04L5/0048 ,  H04L27/2613

摘要： The present invention provides a scattered pilot (SP) location detector capable of detecting patterns of SP symbols promptly without using a TMCC signal. The SP location detector comprises a multiplier which multiplies received signals generated by demodulating OFDM modulation signals in which pilot symbols are dispersively disposed in accordance with four types of patterns and which are transmitted periodically, by a pseudo-random number bit sequence, four arithmetic circuits which are respectively provided corresponding to the four types of patterns and which respectively extract pilot symbols corresponding to respective patterns from results of multiplication by the multiplier and calculate sums of phase differences between the extracted pilot symbols, followed by outputting absolute values thereof, and a pattern detection circuit which detects the corresponding arithmetic circuit maximum in the calculated absolute value from within the four arithmetic circuits.

摘要翻译： 本发明提供一种能够在不使用TMCC信号的情况下迅速地检测SP符号的图案的散射导频（SP）位置检测器。 SP位置检测器包括乘法器，其乘以通过解调OFDM调制信号而产生的接收信号，其中导频符号根据四种类型的模式被分散布置，并且通过伪随机数比特序列周期性地传输，四个运算电路 分别对应于四种类型的图案提供，并且分别从由乘法器的乘法结果分别提取对应于各个图案的导频符号，并且计算提取的导频符号之间的相位差的和，随后输出其绝对值，以及模式检测 电路，其在四个运算电路内检测计算出的绝对值中相应的算术电路最大值。

公开(公告)号：US11003124B2

公开(公告)日：2021-05-11

申请号：US16903734

申请日：2020-06-17

申请人： Masato Tanaka ,  Keiji Kunimi ,  Masaki Yoshino ,  Kazumi Suzuki

发明人： Masato Tanaka ,  Keiji Kunimi ,  Masaki Yoshino ,  Kazumi Suzuki

IPC分类号： G03G15/00 ,  G03G15/20 ,  G03G21/04

摘要： An image forming apparatus including an image forming unit, a fixing device, and circuitry is provided. The image forming unit is configured to perform a special image forming operation that forms a color toner image and a special toner image with a color toner and a special toner, respectively, on a recording medium and a normal image forming operation that forms the color toner image without forming the special toner image on the recording medium. The fixing device is configured to fix the color toner image and the special toner image on the recording medium. The circuitry is configured to perform, in the special image forming operation, a toner amount suppression control that makes an amount of the color toner on the recording medium per unit area smaller than that in the normal image forming operation.