format:
event1 adc_ch1 time_ch1 adc_ch2 time_ch2 ... event2 adc_ch1 time_ch1 adc_ch2 time_ch2 ...
event1 adc_ch1 time_ch1 adc_ch2 time_ch2 ... event2 adc_ch1 time_ch1 adc_ch2 time_ch2