From: Ben Verwer (Ben_Verwer@BDIS.Com)
Date: Wed Oct 28 1998 - 13:10:48 EST
Ray, The short answer to: "Do those sorters have 256 channels per decade, or do they have four decades?", is: 256 channels per decade. Here's what I've been able to find: The front panel display on the FACStar (or FACStar+) had been designed at first for 256 channels, and had only 3 digits to display the sort windows in. When the decision was made to use 10 bit ADC's, rather than delaying release, the team decided to collapse everything greater than 1000 into channel 1000. 1000 is the value send to the computer. If the sort window is set at 999, the sort window will expand to 1023 (or its analog equivalent as the rectangular sort windows are done in analog). In the Vantage SE the analog rectangular sort windows are no more and the values now range from 0-1023, so the answer is: 256 channels per decade AND 4 decades. As for the conversion between channels and linear values, CellQuest uses the formula: 10^(4*channel/1024), so the value 10000 is never reached. To add 1 to the channel number to make it reach 10000, at the expense of reaching the value 1 at the bottom would be equally valid, but since we currently do it the other way, I don't see the big advantage of changing. Ben
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