DSO5202P Frequency

amy

Customer Consultation


I just bayed a oscilloscope dso5202p and question occur,

when i watch a sin or triangular wave, not for square, on the screen
(ref. 5.1 section of owner manual point 10 frequency) I see the
frequency but when magnify the scale(section 4.4 of manual) by vertical
knob VOLT/Div the frequency value it change

if enlarge the wave under 100mV. Why?

I also update the firmware at the latest version.

You can see that in the enclosed example 1 and 2, the ex1 is real frequency.

Best regards



  


Reply


In the two pictures, except for the different VOLT/div , the other settings are the same, right?.

In Ex2_01, has the frequency value been maintained at 1.601KHz?

loris58

this above was my question
In the two pictures the settings are the same, in the first the frequency is 70Hz as take it from generator wave in the second also the frequency remain at 70Hz  except
VOLT/div for zoom the wave. My question was, why the displayed frequency change?

amy

The possible reason is that your signal is noisy.
It is recommended to set the coupling mode to Noise reject or HF reject to try.

loris58

Well, I tryed to follow Your suggests, in order,
1)I set coupling NoiseReject the frequency it remain at 70HZ till 100mV V / div (little bit better) then if I go down 100mV I have same problem as describe above
2) I set coupling HF Reject the frequency it remain at 70HZ till 20mV V / div (much better) then if I go down again I have same problem as describe above
In all the cases when magnify the amplitude I see the frequency changements only in the  display window at the bottom while on the beside menu "AUTOSET" the displayed frequency it does not change and so remain stable at 70Hz

amy

The frequency in the lower right corner of the display window is calculated by the FPGA based on the trigger. The frequency of the measurement function is calculated based on the collected waveform data. The sensitivity of the two measurements is different.
If you do not want the noise of the signal to affect the frequency measurement result, it is recommended to use the measurement function to measure the frequency.
Also you can also use average acquisition to reduce noise, so that the measurement results are more stable.
However, the frequency in the lower right corner of the display window is not affected by the average acquisition.

loris58

Ok, That's  clear
Thank You

loris58

one more question, the movement of  knob "V0"  how shoul be? by click by click as step by step along the menu or continous linear?

amy

Sorry, I can't understand what you mean.