During a seven-day auction on eBay that ended on May 29, Novocin says he sold four items, including an X-Band Weather Radar Modulator for and a high-frequency radio circuit card for .
The phenomenon that the effect of the highfrequency modulation is better than that of the low frequency modulation is explained, and general rules of choosing modulator parameters are also presented.
解释了高频调制效果比低频调制好的实验现象，并且给出了确定调制器参数的一般原则。
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The modulator quantizes the input signal and move the low frequency inband quantization noise to high frequency.