外文翻譯---核譜脈沖數(shù)字成形處理-其他專業(yè)-全文預(yù)覽
【正文】 synthesized gaussian filter. If the integration time extends beyond the width of the prefilter impulse response by an amount greater than the longest charge collection time, any sensitivity to ballistic deficit is eliminated. The GI filter is quite plex and emphasizes low frequency extraneous noise sources such as microphony and power supply ripple. These factors make the filter expensive and difficult to design and to use in an optimum manner, especially when the measurement asks for a great number of gated integrators. Moreover, it produces very long dead time and is unable to correct for trapping losses. The Harwell filter removes the effects of collection time variations by starting the processing time when the detector charge is fully collected and the preamplifier output is flat. The filter presents many of the drawbacks of the GI one and, like the GI, it does not pensate for trapping losses. On the other hand, to avoid the above mentioned difficulties and limits, BD rises when using a short peaking time unipolar semigaussian shaper without GI. If the shaper is driven by a step function with greater than zero rise time T (it is the special case in which the charge arrival times are distributed uniformly over a period T different from zero, and randomly variable from pulse to pulse), the relative BD is proportional to (T/tp) , where tp is the peaking time for output with zero rise time input signal. The longer the rise time con
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鄂ICP備17016276號-1