公开(公告)号：US4673871A

公开(公告)日：1987-06-16

申请号：US812630

申请日：1985-12-23

申请人： John D. Brown ,  Peter Gladdish ,  Michael A. McCormick

发明人： John D. Brown ,  Peter Gladdish ,  Michael A. McCormick

IPC分类号： G01H3/00 ,  B64F5/00 ,  G10K15/00 ,  H03B29/00 ,  H03K3/84 ,  G01R19/00

CPC分类号： H03B29/00 ,  H03K3/84

摘要： A digital noise generator for use in aeroengine noise testing can accurately and repeatably reproduce a standard noise spectrum so that differing noise analysis systems can be calibrated to a common standard. The noise generator comprises a pseudo-random binary sequence generator which is fed with a low clock frequency derived from a high frequency crystal oscillator. The generator produces a pseudo-random noise single bit signal which is fed to the most significant bit input of a digital to analogue converter, whose other inputs are fed with simulated tone data residing within an EPROM, the pseudo-random and tone noise thereby being digitally summed before conversion to an output analogue signal of desired spectral characteristics.

摘要翻译： 用于航空发动机噪声测试的数字噪声发生器可以精确和可重复地再现标准噪声谱，从而可以将不同的噪声分析系统校准为通用标准。 该噪声发生器包括伪随机二进制序列发生器，该发生器馈送有从高频晶体振荡器得到的低时钟频率。 发生器产生伪随机噪声单比特信号，该信号被馈送到数模转换器的最高有效位输入端，其数字模拟转换器的其它输入端馈送驻留在EPROM内的模拟音调数据，因此，伪随机和音调噪声 在转换为所需频谱特性的输出模拟信号之前进行数字求和。

公开(公告)号：US4438406A

公开(公告)日：1984-03-20

申请号：US432824

申请日：1982-10-05

申请人： Michael A. McCormick ,  Peter Gladdish

发明人： Michael A. McCormick ,  Peter Gladdish

IPC分类号： G01R15/08 ,  G01R23/165 ,  H03B19/06 ,  H03F3/68

CPC分类号： G01R23/165 ,  G01R15/08

摘要： A signal processor for use in association with a frequency analyzer, can operate in the frequency translation mode or the filter mode.The signal processor comprises a first low pass filter, the signal from which is fed to two first parallel programmable gain amplifiers controlled by a first digital function controller. The signals then pass via two, second low pass filters to two second programmable gain amplifiers controlled by a second digital function controller. The signals from the second amplifiers are then added by an adder and filtered by a third low pass filter.The first controller is controlled by a frequency signal equal to the frequency in the middle of the bandwidth being translated and the first filter is controlled by a frequency which is a multiple of the control frequency to the first controller.In the range translation mode, the second filters and second controller have a control signal equal to the bandwidth frequency and the third filter is controlled by a signal which is a multiple of the control signal to the second filter and the second controller.In the filter mode, the cntrol signals to the first and second controllers are equal to each other and the control signals to the first and third are equal to each other.

摘要翻译： 与频率分析仪相关联使用的信号处理器可以以频率转换模式或滤波器模式工作。 信号处理器包括第一低通滤波器，该信号被馈送到由第一数字功能控制器控制的两个第一并行可编程增益放大器。 然后，信号经由两个第二低通滤波器通过由第二数字功能控制器控制的两个第二可编程增益放大器。 来自第二放大器的信号然后由加法器相加并由第三低通滤波器滤波。 第一控制器由等于被转换带宽中间的频率的频率信号控制，并且第一滤波器由对第一控制器的控制频率的倍数的频率控制。 在范围转换模式中，第二滤波器和第二控制器具有等于带宽频率的控制信号，并且第三滤波器由作为到第二滤波器和第二控制器的控制信号的倍数的信号控制。 在滤波器模式中，到第一和第二控制器的cntrol信号彼此相等，并且到第一和第三控制器的控制信号彼此相等。