Integration time = 6min, no gate delay for either channel-1 or channel-2.

The configurations of the three data are the same excpet for different ND. The analog signal at near-range and PC signal at far-range look linear. The ratio of data2/data3 for channel 1 is not so flat probably due to the weak signal. The ratio of either data1/data2 or data2/data3 is still bigger than 10.

Why the sinal under 1km looks more linear in this test compared to the ND test#1? Background correction. This test is done during nighttime and test#1 is done during daytime.

For details, please look at Data1/data2 and Data2/data3 PDF files.