Elenco 30MHz Dual Trace - Manual (Page 60)

57
APPLICATION
Method No.2
(Refer to Fig.16)
The above procedure allows 45 per division, which may not give the desired
accuracy for small phase differences.
If greater accuracy is required, the sweep TIME/DIV setting may be changed to
expand the display as shown in Fig.
, but the VAR SWEEP setting must not be to
touched. If necessary, the TRIG LEVEL may be readjusted. For this type of
operation, the relationship of one division to 45 no longer holds. Instead the
following equation must be used:
Phase diff = Hor div x 45/div x
Where:
A = New TIME/DIV setting.
B = Original TIME/DIV setting.
A simpler method of obtaining more accuracy quickly is to simply use X10
magnification for a scale factor of 4.5 /division.
°
16
°
°
Fig.16 Measuring Small Phase Difference
100
90
10
0
Phase difference
A
B
100
90
10
0
One cycle adjusted to 8 div.
Phase difference
Expanded sweep waveform display.