公开(公告)号：US4855894A

公开(公告)日：1989-08-08

申请号：US198576

申请日：1988-05-25

申请人： Nobumitsu Asahi ,  Tetsuo Ikeda ,  Seiji Kawase

发明人： Nobumitsu Asahi ,  Tetsuo Ikeda ,  Seiji Kawase

IPC分类号： H03D7/00 ,  H02M5/00

CPC分类号： H03D7/00 ,  H03D2200/0017 ,  H03D2200/005 ,  H03D2200/0052 ,  H03D2200/006

摘要： A frequency converting apparatus including a sample circuit and a bandpass filter wherein an input analog signal is sampled at predetermined periods only for predetermined time intervals to produce or increase the harmonic components of the original analog signal, a desired frequency component is extracted through the bandpass filter from the harmonic components to thereby convert the original signal having a particular frequency band to a signal having a higher-frequency band.

摘要翻译： 一种包括采样电路和带通滤波器的频率转换装置，其中输入模拟信号仅在预定时间间隔被采样以产生或增加原始模拟信号的谐波分量，通过带通滤波器提取期望的频率分量 从而将具有特定频带的原始信号转换为具有较高频带的信号。

公开(公告)号：US5115468A

公开(公告)日：1992-05-19

申请号：US614552

申请日：1990-05-09

申请人： Nobumitsu Asahi ,  Seiji Kawase

发明人： Nobumitsu Asahi ,  Seiji Kawase

IPC分类号： H03C1/60 ,  H04L27/04

CPC分类号： H03C1/60

摘要： A digital SSB modulator in which an analog signal such as a vocal signal is temporarily converted to a digital signal, which is then subjected to SSB modulation using digital phase shifters and digital orthogonal amplitude modulators, and the resulting signal is converted back to an analog modulated signal. A digital filter may be provided after each digital phase shifter for eliminating direct-current signal components. Another digital filter may be provided after each digital orthogonal amplitude modulator for eliminating carrier signal components.

摘要翻译： 其中诸如声音信号的模拟信号被暂时地转换成数字信号的数字SSB调制器，然后使用数字移相器和数字正交幅度调制器对其进行SSB调制，并将得到的信号转换回模拟调制 信号。 可以在每个数字移相器之后提供数字滤波器，以消除直流信号分量。 可以在每个数字正交幅度调制器之后提供另一数字滤波器，以消除载波信号分量。

公开(公告)号：US4857859A

公开(公告)日：1989-08-15

申请号：US208134

申请日：1988-06-17

申请人： Nobumitsu Asahi ,  Akira Nakazawa

发明人： Nobumitsu Asahi ,  Akira Nakazawa

IPC分类号： H03D1/00 ,  H03D1/02

CPC分类号： H03D1/02

摘要： An AM demodulator of a digital signal processing type wherein an analog AM signal is converted to a digital AM signal, the digital AM signal is squared and a one sample-delayed version of the digital AM signal is squared, these squared signals are added, and the square root of the resulting sum of the squared signals is extracted as an AM demodulated signal. The demodulator comprises a detector for detecting the level of a sum signal representing the sum of the squared signals, an upward bit shifter for bit shifting upwardly the sum signal on the basis of the detection output from the level detector, a polynomial calculator for approximately extracting the square root of the sum signal, and a downward bit shifter for bit shifting downwardly the output signal from the polynomial calculator.

摘要翻译： 一种数字信号处理类型的AM解调器，其中模拟AM信号被转换为数字AM信号，数字AM信号被平方，并且数字AM信号的一个采样延迟版本被平方，这些平方信号被相加，并且 所得到的平方信号之和的平方根被提取为AM解调信号。 该解调器包括检测器，用于检测表示平方信号之和的和信号的电平;一个向上位移位器，用于根据电平检测器的检测输出向上移位和信号;一个多项式计算器， 和信号的平方根，以及用于向下偏移来自多项式计算器的输出信号的向下位移位器。

公开(公告)号：US4136260A

公开(公告)日：1979-01-23

申请号：US797770

申请日：1977-05-17

申请人： Nobumitsu Asahi

发明人： Nobumitsu Asahi

IPC分类号： H04S1/00 ,  H04R5/04

CPC分类号： H04S1/005

摘要： In stereo sound reproduction circuitry for use with a stereo signal source and stereo headphones, the improvement of dip filter means disposed between the stereo signal source and the stereo headphones, the dip filter means having a dip in the transmission characteristic thereof, the dip being in substantially the same frequency position as a dip which occurs in the sound pressure frequency response characteristic at the ear canal entrance when a sound source is disposed in front of a listener.