Hi zachs,
if you have to measure a peak valu, you will need a peak detector or sample/hold circuit, my be some later...
Your ADC has a full range input bandwith of ca 100MHz, this means: your signal at internal ADC-input is after ca. 3.5sec at the true value.
This means, at thes time will take a sample, but your signal is yet not at the peak!May be you have it only in the 5.th or tenth reading/conversion_I dont know the (time) parameter s of a lighting signal.
Thes is a good job for your PIC.
You have two different frequences to see:
1,
signal repetition rate>> may be mili/pico Hz-or?
2,
needed (3dB!!) system badwith, derived from pulse-edge time, remember-3dB, usually you need more hamonics to process as basic(3dB) frequency
, telld as Fouriers "Signal theorem".
3,
I think its better if you plans more phases and build every time more complex your dataaquision system.
To end you need a so called MCA=multi channel analyser to build.
May be you can search for that (& find) on the web.
MCA= you have very speedy conversions and do storage the values from all that, after aquisition is completed or memory is full
, you take all the same amplitudes in a group and write a histogramm from their counts...
For exanpl.:
Max. counts are 255(full range): your system aquired 10x 122, 5x 56 &6x 67, with this 3 beams(column) you have have a relative demonstrativ picture of your lightings process...
Please check web & Physics article for that, I must go to make my job!
Good luck!
K.
Added after 2 hours 19 minutes:
I think a Epson SG-310 SCF C 32.0MHz, Farnell 127-8068 is a good compromiss as ACMOS-Clk osci, and relative cheap...
It NEEDS 3V3!
I believe, its is bessser to design on 3V3, then needs less power for same speed.
Other Possibility is to take 32 MHz Quartz to PIC & buffer it, with Tiny ACMOS SOT-5 ICs, to ADS931, but all in small distances please...
K.