The principle of oscilloscopes is used to show the relative size of the wavelength range on the oscilloscope to reflect the relative size of the maximum voltage value added to the oscilloscope y-diversion plate, thus reflecting the size of the maximum voltage dynamic generated by electromagnetic sensors. Thus, the relationship between the induction of electrical motion and its creation can be studied with the help of oscilloscopes. It consists mainly of instruments for measuring the shape of electrical or pulse current waves and consists of electro-pipe amplifiers, scan convulsors, cathode ray tubes, etc. In addition to observing the wave shape of the current, frequency, voltage intensity, etc. Can be measured. All cyclical physical processes that can be transformed into electrical effects can be observed using oscilloscopes。
Analysis of the measurement methods of oscillators
The four measurements of voltage, time, phase and frequency of oscillators are analysed below。
Measurement of voltage
Any measurements using oscilloscopes are attributed to the measurement of voltage. The oscilloscope can measure the voltage range of various waves, both direct current voltage and sine voltage, and pulse or non-sine voltage. It is more useful to measure the voltage bands of parts of a pulsed voltage wave, such as upper impulses or top drops. This is not comparable to any other electrovoltometer。
Direct measurements
The direct measurement method is to measure directly the altitude of the measured voltage waveform from the screen and then convert it to a voltage value. When quantifying voltage, the micro-tips of the y-axis sensitivity switch are generally transferred to the “calibration” position so that the measured voltage values can be calculated directly from the indicator values of “v/div” and the vertical coordinates taken from the detected signal. So, the direct measurement is also called the ruler。
(1) exchange of voltage measurements
Places the y-axis input coupling switch at the "ac " position, showing the communication composition of the input wave. If the frequency of the communication signal is low, the y-axis input coupling switch should be placed at " dc " 。
A waveform will be moved to the centre of the oscilloscope, and a "v/div" switch will be used to control the waveform within the active working area of the screen, to read the magnitude of h in the direction of the y-axis of the entire waveform by the fraction of the coordinate scale table, and the peak-peak vp-p of the measured voltage may equal the product of the " v/div" switch indicator to h. If probe measurements are used, the decay of the probe shall be calculated by multiplying the above calculation by 10.
For example, the "v/div" axle sensitivity switch "v/div" of the oscillator is at level 0. 2 and the measured wave shape is at the coordinates range h5div of the y axis, and the peak-peak value of the signal voltage is 1v. If measured by a probe, the peak-peak value of the measured signal voltage is 10v.
(2) measurement of direct current voltage
Puts the y-axis input coupling switch in a " ground " position, triggers the switch in an " automatic " position so that the screen displays a horizontal scanning line, which is zero。
Enter the y-axis into the coupling switch position at the "dc" position and add to the measured voltage, at which point the scanner produces a jump-shift h in the direction of the y-axis, which is the product of the "v/div" switch indicator and h。
Direct measurements are simple and simple, but with significant errors. Errors are caused by error in readings, visions and system errors in oscilloscopes (depressors, deflectors, oscilloscope edge effects)。
Comparative measurements
The comparative measurement method is the measurement of voltage by comparing a known standard voltage waveform with the measured voltage waveform。
The y-axis channel of the voltage vx oscilloscope will be fed to regulate the y-axis sensitivity selection switch "v/div" and its micro-tip buttons, so that the fluorescent screen displays and records a measurable height hx, and the "v/div" switch and micro-tip button position remain unchanged. Remove the measured voltage, enter a known adjustable standard voltage vs into the y axis and adjust the output range of the standard voltage so that it shows the same magnitude as the measured voltage. At this point, the output range of the standard voltage is equal to that of the measured voltage. Comparative measurements of voltage avoid vertical system causing and error, thus increasing measurement accuracy。
B. Time measurement
The oscillator time matrix produces a linear line of time, so that wave-shaped time parameters can be measured using the horizontal scale of the fluorescent screen, such as the repetition cycle of periodic signals, the width of pulse signals, time spacing, lifting time (front) and downtime (backward), time difference of two signals, etc。
When the “micro-modification” device of the oscilloscope speed switch “t/div” is transferred to the calibration position, the time represented by the wave shape shown in the horizontal orientation scale can be calculated in direct reading to the indicator value of the “t/div” switch, thus obtaining more precise time parameters for the detected signal。
C. Phase measurements
It is practical to measure the phase difference between two sine voltages using oscilloscopes, which can measure frequency and time, but cannot directly measure the phase relationship between sine voltages. There are many methods of measuring the phase using oscilloscopes, and only a few simple methods are described below。
Double-tracking
Double-trace is used to measure the phase relationship by comparing directly the wave shape of two measured voltages on the fluorescent screen. When measured, the signal ahead of the phase is connected to the yb channel, while the other signal is connected to the ya channel. Select yb to trigger. The "t/div" switch is adjusted so that a cycle of the measured wave form accurately covers 8 div on a horizontal ruler, so that the angle of a period is 360°8 equal to 45° per 1 div. Read the gap t at the horizontal axis between the upper and lateral waves, and calculate the difference in phase by the lower:
=45°/divxt(div)
If t=1. 5 div, φ45°/divx1. 5 div=67. 5°
2. Lisa graphic phase
The x-axis selection of the oscillator is placed at the x-axis input position, the signal u1 accesss the y-axis input end of the oscillator, and the signal u2 accesss the x-axis input end of the oscillator. Appropriately regulates the associated knobs on the oscilloscope panel so that an ellipse of the fluorescent screen (which may be a positive circle or an oscillation in exceptional cases)。
D. Measurement of frequencies
The frequency of signals is measured by oscilloscopes, and two basic methods are described below。
1. Periodicity
For any periodic signal, the above-mentioned time interval can be measured by measuring the time t for each cycle, followed by the lower-forming frequency f = 1/t
For example, the waveform shown on the oscilloscope is 8 div for one cycle, the "t/div" switch has a "1 ms" position and its "misort" position is "calibrated". The periodicity and frequency are calculated as follows:
T=1us/divx8div=8us
F = 1/8us = 125khz
So, the measured waveform frequency is 125 khz.
2. Lisayan graphical frequency
X-y working methods for oscilloscopes, detected signals into the y axis, standard frequency signals into the "x interface" and slowly changing the standard frequencies to multiple the frequency of the two signals, e. G. Fx:
Fy = 1:2, which produces a stable lee shayol figure on the fluorescent screen。
Attention in the use of oscillators
The safety and security of the personnel of the instrument operator, the normal operation of the instrument within the safety limits, and the assurance of the accuracy of the measuring wave shape and the reliability of the data. Therefore, in the use of instruments, it should be noted that:
General-purpose oscillators minimize the diameter of the light points by adjusting the brightness and focus rotor buttons in order to make the wave shape clear and reduce test error; do not keep the light points in motion, otherwise a little bit of the electronic beam is appropriate to create a shadow on the fluorescent screen and damage the fluorescent screen。
Measurement systems - e. G. Oscilloscopes, signal sources, printers, computers, etc. The terrestrial line of equipment, such as instruments, electronic components, circuit boards and electrical power supply from the detected equipment, must be connected to the public ground (the earth)。
3. When the tds200/tds100/tds2000 series digital oscillator is used in conjunction with the probe, only the wave shape of the signal (the detected signal is on the ground and the signal end output is less than 300 vcat ii) can be measured. It is absolutely impossible to measure the floating signal of an electronic device that cannot be isolated from the municipal electricity ac220v. (float is unconnected to the earth, otherwise it causes damage to instruments, such as testing electromagnetic furnaces
4. The shell of the universal oscillator, the signal input end bnc plug metal outer circle, the probe wire, and the ac220v power plug wire end are all connected. If the instrument is used without a line and is measured directly by a probe against a floating signal, the instrument produces a difference in the level of power relative to the ground; the voltage value is equal to the difference in the level of power between the spotted device and the ground. This would pose a serious security risk to instrument operators, oscillators and detectable electronic equipment。
5. Users who are required to measure such types of products as switch-off power (trigger primary, circuit control), ups (uninterruptible power supply), electro-flowers, energy-saving lamps, frequency transformers, or other electronic devices that cannot be isolated from municipal electric ac220v are required to use dp100 high-pressure isolation differential probes。
In addition to this, thermal electronics avoid frequent turn-off, turn-off, and before turning off, turn the luminous retorts to the end along the reverse clockwise, minimize the brightness and then break the power switch。
