From: W.J. Llope (llope_at_physics.rice.edu)
Date: Thu Jan 23 2003 - 12:12:36 EST
>Bill,
>8 dB is a factor of 6.3 in power (dB = 10 log [P2/P1]), but only 2.5
>in amplitude (dB = 20 log [A2/A1])
yep - that's exactly what i got backwards... thanks....
>since power goes as the square of amplitude. I think you are seeing
>exactly the right relationship to within the precision of the
>attenuators. No problem in adding attenuation is we need more
>range. I can also make differential splitters with the needed ratio.
actually looking at all the data we have so far the present
scale isn't too bad. but let's talk about the home-grown
splitters - maybe on the phone?
i'll try to catch you in your office sometime this afternoon...
take care,
bill
>John
>
>At 3:42 PM -0600 1/22/03, W.J. Llope wrote:
>>hello - just some new results from the localmon data...
>>
>>the correlation between the high and low range
>>pVPD ADC values for a given channel is very tight. this
>>makes the rationalization of these two scales very easy...
>>
>>see the attached for (LR_adc-pedestal) in blue and
>>(HR_adc-pedestal)/slope in magenta for pvpd ch 0,
>>where "slope" is the scale factor extracted extremely
>>accurately from fits of HR vs LR in single chs...
>>after pedestal subtraction and scaling the HR ADC
>>for the attenuation the resulting adc dustributions match
>>up very well in shape i'd say....
>>
>>one puzzle at the moment (at least in my mind) is
>>that these scale factors are only a factor of ~2.4, while
>>the attenuators in front of the HR ADCs are 8 dB...
>>i.e. i would have thought the HR ADCs would be more attenuated
>>by more like a factor of 6.... comments?
>>
>>regards,
>> bill
--W.J. Llope, Ph.D. Res. Assoc. Professor T.W. Bonner Nuclear Laboratory phone: 713-348-4741 Rice University, MS-315 fax: 713-348-5215 6100 S. Main St. Houston, TX 77005-1892 e-mail: llope_at_physics.rice.edu WWW home: http://wjllope.rice.edu/default.html
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