How to adjust the use of Puyuan oscilloscope

How to adjust and use Puyuan oscilloscope

As an electronic engineer, we will use oscilloscopes in testing circuits. As a domestic oscilloscope, Puyuan Precision Oscilloscope is a digital oscilloscope designed to meet the design, debugging, and testing needs of the most extensive mainstream digital oscilloscope market. Using an oscilloscope, you can observe and measure changes in different signals over time or signals. Antai Test will introduce to you how to adjust and use Puyuan oscilloscope.

How to adjust and use Puyuan oscilloscope?

1. Power on the oscilloscope and preheat;

2. Adjust the relevant knobs on the low-frequency signal generator panel so that the output signal is a required frequency and voltage value (for example, 1000Hz, 5mV).

3. Use an oscilloscope to observe the frequency, period and amplitude of the output signal of the low-frequency signal generator, and compare it with the frequency and voltage value of the output signal displayed on the panel of the low-frequency signal generator to see if it is consistent.

Puyuan oscilloscope measurement method

1. Voltage measurement

When measuring the input signal voltage, the "fine adjustment" knob of the sensitivity selection switch "V/div" should be turned clockwise to the "calibration" position.

In this way, the voltage value of the measured signal can be directly calculated according to the indicated value of "V/div". Since the measured signal generally contains AC components and DC components, attention should be paid to selecting the input coupling switch during testing.

① Measurement of AC voltage

a. Set the Y-axis input coupling switch "DC-⊥-AC" to "AC". If the signal frequency is low, it should be set to "DC".

b. Move the signal waveform under test to the center of the oscilloscope screen, and read the number of scales occupied by the entire waveform in the Y-axis direction according to the divisions of the coordinate scale.

c. If a probe is used for measurement, the attenuation of the probe should be calculated in the measurement results.

For example: the Y-axis sensitivity switch "V/div" of a dual-trace oscilloscope is at the "0.1V/div" position, and the "fine adjustment" is at the calibration position. If the Y-axis coordinate amplitude Y occupied by the measured signal waveform is 4div , then the peak-peak value of the signal voltage at this time is 0.4V

VP-P=V/div×Y(div)=O.1×4=0.4(V)

The signal voltage (effective value) is:

V=(0.4÷2)×0.707=0.1414(V)

If a probe is used for measurement, the switch position on the oscilloscope panel remains unchanged, and the displayed waveform amplitude is still 4div, then considering the probe attenuation factor of 10 times, the effective value of the measured signal voltage is:

V=(0.4÷2)×0.707×10=1.414(V)

② Measurement of DC voltage

a. Set the trigger mode switch to the "auto" or "high frequency" self-excitation working state, and adjust the relevant knobs so that the horizontal baseline is displayed on the oscilloscope screen.

b. Set the Y-axis input coupling switch "DC-⊥-AC" to the "⊥" position, and adjust the vertical shift knob so that the time baseline is located at the zero-level reference baseline position in the middle of the oscilloscope screen. The time baseline position at this time That is the position of the zero-level reference baseline.

c. Set the Y-axis input coupling switch to the "DC" position and note the distance H between the time baseline and the zero-level reference baseline on the oscilloscope screen.

d. Multiply the indicated value of "V/diV" by the distance H between the time baseline and the zero-level reference baseline to get the DC voltage value of the measured signal.

2. Measurement of period and frequency

First, follow the AC voltage measurement steps to stably display the waveform of the signal being measured on the oscilloscope's screen, then turn the "fine-tuning" knob of the oscilloscope's horizontal scan switch "t/div" clockwise to "Calibration" Location.

Directly read the number of grids A occupied by one cycle of the signal waveform in the horizontal direction from the oscilloscope display screen, and then multiply it with the indicated value of "t/div" to get the period of the signal under test.

For example: the X-axis sensitivity switch "t/div" of the dual-trace oscilloscope is in the "0.5ms/div" position, and the "fine adjustment" is in the calibration position. If the measured signal waveform occupies the number of grids in the horizontal direction in one cycle A is 8div, then the period of the signal at this time is:

T=t/div×A=0.5×8=4(ms)

Since the frequency of the signal is the reciprocal of the period, the frequency of the measured signal is:

f=1/T=1/4=250(Hz)

If multiple cycles of the measured signal can be displayed on the screen of the oscilloscope, the number of cycles of the waveform of the measured signal within the range of 10div in the X-axis direction can be read, and then the signal frequency can be calculated for measurement. Using this method can reduce the frequency measurement error, and its calculation formula is as follows:

f=N/(10×t/div)

3. Phase measurement

A dual-trace oscilloscope can be used to measure the phase relationship between two signals of the same frequency. Set the Y-axis trigger source switch of the oscilloscope to the "YB" position, and then use the internal trigger to start the oscilloscope scan. The relationship between the two signals can be measured. phase difference.

One cycle of the signal occupies 8 divisions in the horizontal direction of the oscilloscope. Since one signal period is 360゜, one div should be 45゜. By reading the number of intervals T (div) between the two signals in the horizontal direction, the phase difference of the two measured signals is obtained by the following calculation method.