How Many Waves Does an MP100 Miss in 5 Seconds at 10 SPS?

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When using an MP100 recording at 10 samples per second (sps) with a 100Hz input signal, the discussion centers on how many waves would be missed in a 5-second recording. The calculations suggest that 90 waves are missed per second, leading to a total of 450 missed waves over 5 seconds, which is not among the provided answer choices. Participants express confusion over the discrepancy and highlight the implications of undersampling, noting that it can result in a distorted representation of the waveform. The conversation emphasizes the importance of understanding sampling rates and their effects on data acquisition. Ultimately, the lack of clarity in the question's parameters complicates the determination of the correct answer.
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If your MP100 is recording at 10 sps and your input analog signal is at 100Hz, how many waves would the data acquisition miss in a 5 s recording?
a. 50
b. 1000
c. 25
d. 500
e. 100

This means that you're sampling every 10 cycles. Then you miss 9/10. so once it goes through 100 cycles (100Hz) 90 waves are missed. Then in 5s, isn't it 450 cycles that would be missed? But that's not in the choice...
A little help please?
 
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jnimagine said:
If your MP100 is recording at 10 sps and your input analog signal is at 100Hz, how many waves would the data acquisition miss in a 5 s recording?
a. 50
b. 1000
c. 25
d. 500
e. 100

This means that you're sampling every 10 cycles. Then you miss 9/10. so once it goes through 100 cycles (100Hz) 90 waves are missed. Then in 5s, isn't it 450 cycles that would be missed? But that's not in the choice...
A little help please?

Yeah, you miss 90 per second for 5 seconds, so I'd say 450 missed cycles also. What turned out to be the answer?
 
berkeman said:
Yeah, you miss 90 per second for 5 seconds, so I'd say 450 missed cycles also. What turned out to be the answer?

well that's the problem... because 450 is not in the choices.. :(
what do you think the best choice is...?
 
jnimagine said:
well that's the problem... because 450 is not in the choices.. :(
what do you think the best choice is...?

Yuk. How about this. The sampling is way undersampling, and if it's exactly synch'ed with the waveform, you will get a DC level out of the undersampler. So you miss all of them. That's what I would say if I was held down and had to take my best guess. Your thoughts?

The problem is that the info given does not include real numbers and tolerances. An undersampled waveform can look pretty dang weird. I use a signal generator and an oscilloscope at an undersampled time base setting as one of my interview questions at my work...
 
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