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The introduction of oscillograph and application
Knowledge Base + 2023.12.12

Study shows dispatch wave implement (Oscilloscope) principle and function, do apply simply.

Oscillograph principle

If plan institute shows the CRT picture of a more adjacent and actual design. The CRT is the heart of oscillograph. Cathode is heated by filament generation heats up a boy far away from home. After these electronic classics that break away from cathode because of be heated control the attraction of grid or be being restrained, be quickened positive pole to attract, and through focusing positive pole and quicken positive pole, repass is perpendicular reach horizontal deflection board, be hit to fluorescent act after deflection. The electron hits fluorescence to act gives off fluorescence and form one window, coating of by tube wall returns cathode and make bout way next.

Horizontal deflection voltage is the toothed wave that oscillograph itself place offers (graph 2) , perpendicular deflection voltage is waited for for what the outside inputs measure voltage question mark.

Graph 3 explain to cite one example.

Graph 3 (A) it is the perpendicular deviation that is added in oscillograph board the sine voltage of the input that go up is undee.

Graph 3 (B) it is oscillograph itself place is offerred add in the level the toothed wave on deflection board.

These two when change voltage wave is a graph in the synthetic effect on oscillograph 3 (C) sine wave.

If cancel the horizontal deflection voltage of oscillograph, if pursue,admiral of fluorescent act shows 3 (D) undee.

The scanning cycle of the horizontal scanning voltage of general oscillograph is adjustable, if we will be toothed the cycle of wave by original 8ms (graph 3 (B) ) increase for 16ms perpendicular input to keep original figure (graph 3 (A) ) changeless both the synthetic graph on oscillograph is a graph 3 (E) .

Let us now more bat around, how to become the undee conversion that shows on screen wait for the voltage that measures signal and frequency truly. If express,be narrated.

It is to use block diagram to make one shew sex describe to the whole structure of oscillograph below (graph 4) . We divide into a few subsystem to explain:

CRT: The place before be like is narrated, include grid of filament, cathode, control, focusing to reach quicken zincous, level and perpendicular deflection board and fluorescent act.

(one) perpendicular signal system: Perpendicular signal system is formed by amplifier of a lot of class. Amplifier trustily magnifies or input question mark damply, make oscillograph can be accepted very large-scale inputs voltage.

(2) horizontal signal system: Horizontal signal system includes amplifier of time base generator, synchronous circuitry and horizontal signal. Synchronous circuitry takes out the input voltage signal of enlarge from perpendicular amplifier, choose constant tension to nod (for example at 0 o'clock, slope is waited a moment) , command time base builder (generate toothed wave) begin scanning 3/4 this action is namely " spark " 3/4 in order to make horizontal deflection voltage can be mixed the in step of perpendicular deflection voltage.

(3) high pressure and low-pressure power source: High-pressured source basically offers what cathode is in charge of to quicken voltage (dc high pressure) , it is the DC of volt of 1200 ~ 2000 normally. Low-pressure power source supplies circuit of the other inside oscillograph to handle the power source of a need. When the toothed wave that if the horizontal deflection voltage of oscillograph replaces oscillograph interior by input of mark of ab extra question,generates, criterion oscillograph can turn a X-Y into constructive machine.

Then we talk way of graph of Li Sha Yo (Lissajous Pattern Method) the principle that applies at measuring frequency. If we are in of oscillograph perpendicular with the level on deflection board, when inputting sine wave voltage respectively, the figure that oscillograph place shows, we say for graph of Li Sha Yo.

Assume we are inputting two signal with equal frequency to be mixed at the level perpendicular deflection board, may appear on screen: Circle, elliptical or be those who tilt is linear. As to it is which kind of graphs, carry the size that inspects two inputs voltage and its are phasic (Phase) and calm.

If is perpendicular if with the level deflection board all does not add any signal, the smooth name a person for a particular job of screen appears at fixed position (if pursue,5 are shown) .