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    Method of reducing electromagnetic emissions (EMI) from LED bar systems
    2.
    发明授权
    Method of reducing electromagnetic emissions (EMI) from LED bar systems 失效
    降低LED条系统的电磁辐射（EMI）的方法

    公开(公告)号：US06762784B2

    公开(公告)日：2004-07-13

    申请号：US09683537

    申请日：2002-01-16

    申请人： Gary R. Skillman

    发明人： Gary R. Skillman

    IPC分类号： B41J247

    CPC分类号： G06F1/10

    摘要： Light emitting diode (LED) bar systems have large surface areas and extensive cabling that carry high frequency clocks and data. As the process speeds increase, the higher clock and data rates become an electromagnetic interference (EMI) problem. As the U.S. federal government restricts EMI emissions, many have turned to shielding techniques. However, a spread spectrum technique now may also reduce peak EMI amplitudes by distributing the EMI energy over a range of frequencies. The pixel data may be clocked into a LED bar system with a varying frequency to spread the energy over the range of the modulation. The same total energy is still emitted from the system, but the peak energy at any particular frequency is reduced.

    摘要翻译： 发光二极管（LED）棒系统具有较大的表面积和大量布线，可承载高频时钟和数据。 随着过程速度的增加，更高的时钟和数据速率成为电磁干扰（EMI）问题。 由于美国联邦政府限制EMI排放，许多人转而采用屏蔽技术。 然而，扩频技术现在也可以通过在一定频率范围内分配EMI能量来降低峰值EMI幅度。 可以将像素数据定时进入具有变化频率的LED条系统，以在调制范围上扩展能量。 相同的总能量仍然从系统发射，但是在任何特定频率下的峰值能量都减少了。

    Direct digital synthesis pixel clock generator
    3.
    发明授权
    Direct digital synthesis pixel clock generator 有权
    直接数字合成像素时钟发生器

    公开(公告)号：US06351277B1

    公开(公告)日：2002-02-26

    申请号：US09680193

    申请日：2000-10-06

    申请人： Gary R. Skillman

    发明人： Gary R. Skillman

    IPC分类号： B41J2435

    CPC分类号： G02B26/127 ,  G06K15/1219

    摘要： A Direct Digital Synthesis pixel clock generator for use in electrophotographic printers. A controller receives a start-of-scan signal and a facet 0 signal. In response, the controller sends a pre-stored frequency control word to a Direct Digital Synthesis Oscillator. The Direct Digital Synthesis Oscillator sends pulses at a frequency that depends on the frequency control word to a Digital Phase Shift Circuit. The controller also applies a sequence of delay profile words to the Digital Phase Shift Circuit. Each delay profile word causes the Digital Phase Shift Circuit to delay a contemporaneous pulse from the Direct Digital Synthesis Oscillator between 0° and 360° degrees, with the actual delay depending upon the delay profile word. The delay profile words are selected such that scan line pixels are “adjusted” in position. A phase-locked-loop circuit integrates and smoothes the frequency step changes. The output of the phase-locked loop circuit is applied to a synchronizer that synchronizes the pixel clocks with the start-of-scan. Alternatively, the controller applies a sequence of frequency profile words to a Direct Digital Synthesis Oscillator. The Direct Digital Synthesis Oscillator then generates pulses at a rate that depends upon the applied frequency profile word. The frequency profile words are selected such that the pixels are “adjusted” in position. A phase-locked-loop circuit then integrates and smoothes the output of the Direct Digital Synthesis Oscillator. The resulting pulse frequency is applied to a synchronizing circuit that synchronizes the pixel clocks with the start-of scan-signals.

    摘要翻译： 用于电子照相打印机的直接数字合成像素时钟发生器。 控制器接收扫描起始信号和小平面0信号。 作为响应，控制器将预先存储的频率控制字发送到直接数字合成振荡器。 直接数字合成振荡器以取决于频率控制字的频率向数字移相电路发送脉冲。 控制器还向数字移相电路施加一系列延迟分布字。 每个延迟分布字使数字移相电路将直接数字合成振荡器的同期脉冲延迟0°至360°，实际延迟取决于延迟分布字。 选择延迟分布字使得扫描线像素在位置“调整”。 锁相环电路集成并平滑频率阶跃变化。 锁相环电路的输出被施加到使像素时钟与扫描开始同步的同步器。 或者，控制器将频率分布字序列应用于直接数字合成振荡器。 然后，直接数字合成振荡器以取决于所施加的频率分布字的速率产生脉冲。 选择频率分布词，使得像素在位置“调整”。 然后锁相环电路对直接数字合成振荡器的输出进行积分和平滑。 所产生的脉冲频率被施加到使像素时钟与扫描信号的起始同步的同步电路。