Task №2

- determine the signal period

 

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- taking into account, that the frequency and period of the signal are included in the measurement range, it is recommended to choose such mode of frequency counter, where measurement error will be minimal.

- calculate the relative error of discreteness in the mode of frequency measurements:

 

 

where Т_count is calculated as in the task 1,and equals 10⁴ ms=10 s

- calculate the relative error of discreteness in the mode of period measuring:

- choose the period of time marks, (as the rule, minimal value), that's Т _m=0,1 µs=10^-7s.

- give an assessment of the value of multiplier n signal period, with the restriction on the counting unit (), N - number of marks, calculated by the counter, q - number of counter digits.

Period multiplier can assume such values n =10⁰; 10¹; 10²; 10³; 10⁴.

 

 

Since 10³<n<10⁴, then the value of period multiplier equals 10³.

- determine the number of marks

 

 

- calculate the relative error of discreteness in the mode of period measuring:

 

 

that is, less than in the mode of frequency measurements, and therefore choose the mode of measurement period.

- for the selected mode define the absolute error ∆ _N, time counting Т_count, and the measurement result of the display.

 

 

Display result is 100.0000 µs.