(4)Fu nctio n of TRIG ALT switch :
Th e TRIG A LT switc h is used to select alternate trigg erin g and alte rnat e dis play whe n the DUAL-trace VERT MODE is
S elec ted (the switc h has on e ffect in the CH1,CH2,o r ADD m odes ).In the a ltern ate triggerin g mo de (when dua l-trace op erati on
is selected ),the trig ger s ourc e alternat es be twe en ch anne l l an d ch annel 2 with each swee p.Th is is conv enie nt fo r che ckin g
a mplitude s,wave sh ape,or waveform period me asureme nts,and ev en p ermits si mult aneo us ob serv atio n of t wo waveform s wh ich
are n ot related in freque ncy or pe riod.Howeve r,this sett ing is not suit able for p hase or timing com pari son measurements .For such
measu rements ,both traces m ust be triggered by the sam e syn c sig nal.
When the C HOP and the T RIG ALT switches are both enga ged during du al-tr ace opera tion , syn chro niza tion of th e dis play is no t
p ossi ble b ecau se th e choppi ng signal beco mes the t rigg er.Use the ALT mo de by itse lf, o r select CH1o r CH 2 as trig ger s ourc e.
S et th e TIME/DIV c ontr ol to display t he de sire d num ber of cycles of the w avefo rm.If the re are too many cy cles disp layed for good
r esolu tion ,swi tch to a fa ster swee p sp eed.If onl y a line is disp layed, try a slower sweep speed .Wh en th e sw eep speed is faster than
the wavefo rm being obs erve d,on ly part of it will be disp layed ,which m ay a ppea r as a str aigh t line for a squ are w ave or p ulse
wave form.
W hen a ce rtain part of th e dis play ed waveform is ne eded to b e exp and ed time wise,a fas ter
s weep speed may be use d.Ho wev er,if the r equi red portio n is apar t from the starting poin t
o f the swe ep, th e require d po rtion may run off the CRT s cree n. In such a case, p ush in
the x 10 MAG butto n. W hen this has b een d one , the displayed wavefo rm will b e
e xpan ded 10 ti mes to th e righ t and lef t with the center of scre en as the cent er of
e xpan sion . The swe ep ti me d urin g the mag nifi catio n op eration is as fo llows:
( Valu e indicate d by TIME/DIV switch k1/1 0
T hus, the u nmagnified maximum swe ep s peed(lu s ec/DIV)c an b e increas ed
wi th the magn ifica tion as follow s:
lus ec/DIV x 1/10 =100 nsec /DIV
4.7 TIME/DIV Control
4.8 Sweep Magniftcation
10x magnificatio n
An y part can be c overed by
me ans of POSITION control
Fig ure 4 -8
21
22
4.9 X-Y Operation
Set the TI ME/div switch to X-Y position.Then the instrument works as an
X-Y oscil loscope.Each input is applied to the instrument as follo ws.
X-axis signal(horizontal axis signal):CH 1 I NPUT
Y-axis signal(vertical axis signal):CH2 INPUT.
Note:When high frequency sign als are displayed in the X-Y operation,pay
atten tion to the frequency b andwidths and phase difference between X and Y-axis.
X-Y operation permit s the oscilloscope to perfor m many meas urements not possible with conventional sweep operation.The
CRT disp lay becomes an electronic grap h of two instantaneous voltages.The display may be a direct compariso n of the two
voltages such as a vectorscope display of video color bar patterns.However,the X-Y mode can be used to graph almost any
dynamic characteristic if a transducer is uesd to change the characteristic( frequency,t emperature,velocity,etc.)in to a voltage.
One common application is frequency res ponse measurements,where the Y-axis corresponds to s ignal amplitude and the X-axis
corresponds to frequency.
1.Set the TIME /div control to the X-Y position (fully counterclockwise).In this mode,channel 1becomes the X-axis
inpu t and channel 2 becomes the Y-axis input.
2.The X and Y positions are now adjusted us ing the horizontal
POSITION and C 2
POSITION controls
H
respectively.
3.Adjust the amount of ve rtical(Y-axis) deflection with the CH2 VOLT S/DIV and VAR controls.
4.A just the amount of horizontal(X-axis) deflection with the CHl VOLTS/DIV and VAR con trols.
d
Y axis(CH 2)
X axis
(CH 1)
Figure 4-9
