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    Precision, wide band pulse width modulator for digital to analog conversion
    1.
    发明授权
    Precision, wide band pulse width modulator for digital to analog conversion 有权
    精密的宽带脉宽调制器，用于数模转换

    公开(公告)号：US06798369B1

    公开(公告)日：2004-09-28

    申请号：US10637413

    申请日：2003-08-08

    申请人： Charles F. Weber

    发明人： Charles F. Weber

    IPC分类号： H03M166

    CPC分类号： H04R3/00 ,  G10H5/10 ,  G10H7/00 ,  G10H2250/545 ,  G11B20/08 ,  G11B20/10527

    摘要： A system for generating an analog signal to produce sound using a precision multiple pulse width modulator circuit is disclosed. The system includes a control circuit, a pulse width modulation circuit, and a mixer circuit. The control circuit includes a memory for storing sound tables. The control circuit senses an event, accesses the sound table associated with the event, retrieves an entry value from the sound table, and communicates the entry value with the pulse width modulation circuit. The pulse width modulation circuit includes (I) number of pulse width modulators and the entry value is represented by a number having (I) places where each pulse width modulator represents a place of the number representing the entry value. The mixer circuit includes multiple resistors. Each resistor is connected to a pulse width modulator from the pulse width modulation circuit on one end and the common node of the mixing circuit on the other end. The resistors have the effect of scaling the signal from each pulse width modulator thereby creating an analog signal at the common node corresponding to the entry value of the sound subtable.

    摘要翻译： 公开了一种使用精密多脉冲宽度调制器电路产生模拟信号产生声音的系统。 该系统包括控制电路，脉宽调制电路和混频电路。 控制电路包括用于存储声表的存储器。 控制电路感测事件，访问与事件相关联的声表，从声表中检索入口值，并将输入值与脉宽调制电路进行通信。 脉冲宽度调制电路包括（I）脉冲宽度调制器的数量，并且入口值由具有（I）位置的数字表示，其中每个脉冲宽度调制器表示表示入口值的数字的位置。 混频器电路包括多个电阻器。 每个电阻器从一端的脉冲宽度调制电路和另一端的混合电路的公共节点连接到脉宽调制器。 电阻器具有对来自每个脉冲宽度调制器的信号进行缩放的效果，从而在与可分离声音的入口值相对应的公共节点处产生模拟信号。

    Enhanced register array accessible by both a system microprocessor and a wavetable audio synthesizer
    4.
    发明授权
    Enhanced register array accessible by both a system microprocessor and a wavetable audio synthesizer 有权
    增强的寄存器阵列可由系统微处理器和波形音频合成器访问

    公开(公告)号：US6058066A

    公开(公告)日：2000-05-02

    申请号：US160992

    申请日：1998-09-25

    申请人： David E. Norris ,  Larry D. Hewitt ,  Jeffrey M. Blumenthal

    发明人： David E. Norris ,  Larry D. Hewitt ,  Jeffrey M. Blumenthal

    IPC分类号： G06F3/16 ,  G06F7/02 ,  G06F9/38 ,  G10H1/00 ,  G10H1/12 ,  G10H7/00 ,  G10H7/02 ,  H03K23/68 ,  H03M3/02 ,  H03M7/32 ,  G11C8/00

    CPC分类号： H03K23/68 ,  G06F3/162 ,  G06F7/026 ,  G06F9/3869 ,  G10H1/0066 ,  G10H1/125 ,  G10H7/002 ,  G10H7/02 ,  G10H2220/315 ,  G10H2230/035 ,  G10H2240/311 ,  G10H2250/191 ,  G10H2250/545 ,  G10H2250/571 ,  G10H2250/605 ,  G10H2250/611

    摘要： A register array accessible by both a system microprocessor and a digital signal processor of a PC audio circuit, comprising: (i) a random access memory (RAM) having a first port connected to a digital signal processor input/output port, and a second port connected to a RAM input/output port; (ii) a register data port connected to the RAM input/output port and having a connection to a register data bus; (iii) timing circuitry for timing the register array operations; (iv) row and column select circuitry for respectively selecting rows and columns in said RAM; and (v) an input/output channel ready signal line connected to said timing circuitry. The RAM includes a plurality of edge bits each of which stores a value indicating whether processing of a row of data values stored in said RAM is active or inactive. The system microprocessor is disabled from accessing the RAM whenever the RAM is not idle or the microprocessor seeks to access a row of the RAM currently subject to access by the digital signal processor. If the microprocessor is disabled from writing data to the RAM, the data may be temporarily stored in the register data port until the microprocessor's access is enabled.

    摘要翻译： 一种可由PC音频电路的系统微处理器和数字信号处理器访问的寄存器阵列，包括：（i）具有连接到数字信号处理器输入/输出端口的第一端口的随机存取存储器（RAM），以及第二 端口连接到RAM输入/输出端口; （ii）连接到RAM输入/输出端口并具有到寄存器数据总线的连接的寄存器数据端口; （iii）用于定时寄存器阵列操作的定时电路; （iv）用于分别在所述RAM中选择行和列的行和列选择电路; 和（v）连接到所述定时电路的输入/输出通道就绪信号线。 RAM包括多个边沿位，每个边沿位存储指示存储在所述RAM中的一行数据值的处理是处于活动还是非活动状态的值。 当RAM不空闲或微处理器寻求访问当前受数字信号处理器访问的RAM的一行时，系统微处理器被禁止访问RAM。 如果微处理器禁止向RAM写入数据，则数据可能会临时存储在寄存器数据端口中，直到微处理器的访问被使能为止。

    Digital sound generating system permitting a shared use of a hardware resource between different type tone generators
    5.
    发明授权
    Digital sound generating system permitting a shared use of a hardware resource between different type tone generators 失效
    数字声音产生系统允许在不同类型的音调发生器之间共享使用硬件资源

    公开(公告)号：US5890119A

    公开(公告)日：1999-03-30

    申请号：US784798

    申请日：1997-01-16

    申请人： Norio Suzuki

    发明人： Norio Suzuki

    IPC分类号： G10H1/02 ,  G10H1/00 ,  G10H7/00 ,  G10H7/02 ,  G10H7/06 ,  G10K15/02 ,  G10L9/18

    CPC分类号： G10H1/0041 ,  G10H7/006 ,  G10H7/06 ,  G10K15/02 ,  G10H2250/095 ,  G10H2250/145 ,  G10H2250/545

    摘要： A digital sound generating system is provided which is capable of, in addition to generating a tone (first waveform data), recording or reproducing PCM sound data representing a human voice or sound of a music piece lasting for a relatively long time (second waveform data). To this end, in the tone generating process, tone waveform sample data is read out from a waveform RAM on the basis of address data given from an address calculating section and is then output as an analog signal via an interpolating section and D/A converter. In reproduction of PCM sound data, the PCM sound data supplied via a CPU interface is transferred using the waveform RAM as a buffer and is then supplied outside of the system through a same channel as in the tone generating process. In recording of PCM sound data, a high-frequency-component removing process is performed, by a filtering calculating section, on PCM sound data received via an A/D converter so as to prevent unwanted aliasing noise. The resultant filtered PCM sound data is then transferred using the waveform RAM as a buffer and output via the CPU interface.

    摘要翻译： 提供了一种数字声音产生系统，除了生成音调（第一波形数据）之外，还能够记录或再现表示相当长时间的音乐的人声或声音的PCM声音数据（第二波形数据 ）。 为此，在乐音产生处理中，基于从地址计算部分给出的地址数据，从波形RAM读出乐音波形采样数据，然后经由内插部分和D / A转换器作为模拟信号输出 。 在PCM声音数据的再现中，通过CPU接口提供的PCM声音数据使用波形RAM作为缓冲器传送，然后通过与音调产生处理中相同的通道在系统外部提供。 在PCM声音数据的记录中，通过滤波计算部分，经由A / D转换器接收的PCM声音数据执行高频分量去除处理，以防止不想要的混叠噪声。 然后使用波形RAM作为缓冲器传送所得到的经滤波的PCM声音数据，并通过CPU接口输出。

    Wavetable audio synthesizer with waveform volume control for eliminating zipper noise
    8.
    发明授权
    Wavetable audio synthesizer with waveform volume control for eliminating zipper noise 失效
    波形音频合成器，具有消除拉链噪音的波形音量控制

    公开(公告)号：US5742695A

    公开(公告)日：1998-04-21

    申请号：US333562

    申请日：1994-11-02

    申请人： David N. Suggs

    发明人： David N. Suggs

    IPC分类号： G06F7/02 ,  G10H7/02 ,  H03K23/68 ,  H03G3/00

    CPC分类号： G10H7/02 ,  G06F7/026 ,  H03K23/68 ,  G10H2210/201 ,  G10H2250/115 ,  G10H2250/545 ,  G10H2250/605 ,  G10H2250/621

    摘要： A wavetable audio synthesizer with means for eliminating zipper noise caused by large volume increments, especially at slower rates of volume increment. The wavetable audio synthesizer includes shift circuitry which stores the value of volume increment in binary format and shifts the value right when the shift circuitry is enabled. Shifting the increment value right divides the value by an amount based on the number of bit positions shifted. For example, in the preferred embodiment, the volume increment value is shifted right three positions, thereby dividing it by three and effectively reducing the increment value. When the synthesizer is programmed to increment the volume at a slow rate, preferably the shift circuitry is automatically enabled. Those volume increment bits which are shifted right may be added to the current value of the volume to provide more resolution to this value.

    摘要翻译： 一种波形音频合成器，具有消除大体积增量引起的拉链噪声的方法，特别是在较慢的音量增量速率下。 波动音频合成器包括移位电路，其存储二进制格式的音量增量值，并且当移位电路被使能时将该值向右移位。 移动增量值右移将基于移位的位位数的数值分开。 例如，在优选实施例中，体积增量值向右移位三个位置，从而将其除以3并有效地减小增量值。 当合成器被编程为以慢速率增加音量时，优选地，移位电路被自动启用。 向右移动的那些音量增量位可以被添加到音量的当前值，以便为该值提供更多的分辨率。

    Method and apparatus for selective reduction of upper harmonic content in digital synthesizer excitation signals
    9.
    发明授权
    Method and apparatus for selective reduction of upper harmonic content in digital synthesizer excitation signals 失效
    数字合成激发信号中选择性还原上和谐内容的方法与装置

    公开(公告)号：US5194684A

    公开(公告)日：1993-03-16

    申请号：US608105

    申请日：1990-11-01

    申请人： Ronald J. Lisle ,  B. Scott McDonald

    发明人： Ronald J. Lisle ,  B. Scott McDonald

    IPC分类号： G10H1/043 ,  G10H1/057 ,  G10H1/06 ,  G10H1/14 ,  G10H5/10 ,  G10H5/12

    CPC分类号： G10H5/10 ,  G10H1/06 ,  G10H2250/545

    摘要： Variable frequency sawtooth waveforms are often utilized as an excitation signal in a digital musical synthesizer. A problem exists at lower sampling rates in such systems due to an aliasing problem which occurs at frequencies near the Nyquist rate. Low pass filtering may be utilized to mask this problem; however, low pass filtering is very time consuming to implement in a ditigal signal processor. The method and apparatus of the present invention reduces the upper harmonic content of a sawtooth waveform by proportionally converting the sawtooth waveform to a triangle waveform in response to variations in the frequency of the sawtooth waveform. This is accomplished by adding a selectable offset to the sawtooth waveform and then taking the absolute value of the resultant waveform. By restoring this waveform to a zero offset, the sawtooth waveform excitation signal will be converted to a triangle waveform having a substantially reduced upper harmonic content. By varying the selectable offset in response to variations in the frequency of the sawtooth waveform, it is possible to efficiently vary the amount of conversion which occurs.

    Electronic musical instrument of waveform memory reading type
    10.
    再颁专利
    Electronic musical instrument of waveform memory reading type 失效

    公开(公告)号：USRE33738E

    公开(公告)日：1991-11-12

    申请号：US828081

    申请日：1986-02-07

    申请人： Takatoshi Okumura

    发明人： Takatoshi Okumura

    IPC分类号： G10H1/08 ,  G10H7/06

    CPC分类号： G10H7/06 ,  G10H1/08 ,  G10H2250/545

    摘要： An electronic musical instrument includes a plurality of address generators for producing address signals corresponding to different tones each varying at a rate synchronous with the frequency of each of the different tones, a waveform memory device including a plurality of addresses for storing at respective addresses a plurality of waveform sample values that constitute a waveform, a circuit for sequentially supplying one after another of the address signals to the waveform memory device to read out the waveform in different rates in a time division multiplexed manner for different tones, and musical tone forming circuits for forming musical tones in accordance with the time division multiplexed waveform outputs of the waveform memory device.