Trio CS-2100A, Instruction Manual, Page: 29 / 42

APPLICATION
• Read the dial setting when
;B sweep points of DELAY
TIME MULTIPLIER © and
_(2)
are in the same position.
[ E X A M P L E ]
The reference signal dial reading is 1.00 w h i l e the second
dial reading is 5 . 3 4 w i t h an A SWEEP T I M E / D I V setting of
2/is.
Substituting the value:
Time difference = ( 5 . 3 4 — 1 . 0 0 ) x 2(jus) = 8 . 6 8
X-Y OPERATION
PHASE MEASUREMENT
Phase m e a s u r e m e n t s may be made w i t h X-Y operation.
Typical applications are in circuits designed to produce a
specific phase shift, and m e a s u r e m e n t of phase shift
distortion in audio amplifiers or other audio networks.
Distortion of a m p l i t u d e is also displayed in the oscilloscope
w a v e f o r m .
To make phase m e a s u r e m e n t s , use the f o l l o w i n g procedure
1. Using an audio signal generator w i t h a pure sinusoidal
signal, apply a sine w a v e test signal at the desired test
frequency to the audio n e t w o r k being tested.
2. Set the signal generator o u t p u t for the normal operating
level of the cirucit being tested. If desired, the circuit's
o u t p u t may be observed on the oscilloscope. If the test
circuit is overdriven, the sine w a v e display on the
oscilloscope is clipped and the signal level m u s t be
reduced.
S I N E of = i
P
A
W H E R E 0 = P H A S E A N G L E
3. Connect the Channel 1 probe to the o u t p u t of the test
circuit.
4. Set the H. D I S P L A Y to X-Y.
5. Connect the Channel 2 INPUT probe to the input of the
test circuit.
6. A d j u s t the Channel 1 and 2 gain controls for a suitable
v i e w i n g size.
7. S o m e typical results are s h o w n above. If the t w o sig-
nals are in phase, the lissajous' pettern is a straight
diagonal line. If the vertical and horizontal gain are
properly adjusted, this line is at a 4 5 ° angle.
A 9 0 ° phase shift produces a circuilar Lissajours' pattern.
Phase shift of less (or more) than 9 0 ° produces an elliptical
Lissajous' pattern. The a m o u n t of phase shift can be
calculated f r o m the oscilloscope trace as s h o w n left below.
FREQUENCY MEASUREMENT
Frequency m e a s u r e m e n t may be m o d e w i t h t h e Lissajous'
pattern, as phase measurement.
Procedure:
1. Connect the sine w a v e of k n o w n frequency to the CH 2
INPUT of the oscilloscope and set the H. D I S P L A Y to
X-Y.
2. Connect the vertical input probe (CH 1 INPUT) t o the
u n k n o w n frequency.
3. A d j u s t the Channel 1 and 2 gain controls for a
convenient, easy-to-read display.
4. The resulting pattern, called a Lissajous pattern, s h o w s
the ratio b e t w e e n the t w o frequencies.
5-12
Unknown frequency
to Vertical Input,
Standard frequency
to Horizontal Input
Ratio of unknown
to standard
1 V? :
1
Note: Any one of these figures, depending upon phase relationship
Using the f o r m u l a :
T i m e difference = (2nd dial reading — 1 st dial reading)
x Delayed s w e e p t i m e (A SWEEP
T I M E / D I V setting)
No amplitude distortion,
no out of phase
Amplitude distortion,
no out of phase
180° out of phase
No amplitude distortion,
out of phase
Amplitude distortion,
out of phase
90° out of phase
See note
See note
Vt : 1
1 : 1
6 : 1