After getting the Siglent SDS1104X-E, i have done some reading about DSO blind time and it's implications. One thing is still unclear to me: As I understand it, after each filling of the memory depth, the DSO needs some time to process the collected data. During that time it is unable to respond to new signals.
But how can it measure the trigger frequency during this time? Or does it ignore the trigger during blind time? But in this case, shouldn't the appearant frequency change if the recorded signal becomes so short that only one trigger is visible before the DSO becomes blind?
I'm also interested how other scopes handle this, not only the siglent.
Signal, via ADC, to digital trigger system is continuous. Independent of blind time. So it can count continuously.
Blind time do not stop this red marked signal (data stream, digitized analog input signal).
How data stream is stored to memory and handled for display. There is also blind time.
You can imagine trigger counter signal is one extra output from this Digital Trigger Circuit what do not sleep when scope have "blind time".
Also same if we talk about bit older analog trigger systems in digital oscilloscopes.
Signal, via analog side pathway, to analog trigger system is continuous. Independent of blind time. So it can count continuously.
Even when digital acquisition system have blind time this analog side pathway to trigger comparators and also trigger counters works continuously. In old analog trigger system it is perhaps more easy to understand that blind time do not affect this side pathway where from can take signal to trigger counter.
Conventional analog side pathway trigger system (fun is this text in image).