1. Using an audio signal generator with a pure s i -
nusoidal signal, apply a sine wave test signal at
the desired test frequency to the audio
network being tested.
2. Set the signal generator output for the normal
operating level of the circuit being tested. If
desired, the circuit's output may be observed
on the oscilloscope. If the test circuit is
overdriven, the sine wave display is clipped
and the signal level must be reduced.
3. Connect the CH 1 probe to the output of the
test circuit.
4. Set the S W E E P T I M E / D I V to X - Y .
5. Connect the C H 2 probe to the input of the test
circuit.
The input and output test connections to the
vertical and horizontal oscilloscope inputs may
be reversed.)
6. Adjust the C H 1 and C H 2 gain controls for a
suitable viewing size.
7. Some typical results are shown in
Fig. 25.
If
the two signals are in phase, the oscilloscope
trace is a straight line. If the vertical and ho-
rizontal gain are properly adjusted, this line is
at 4 5 ° angle. A 9 0 ° phase shift produces a
circular oscilloscope pattern. Phase shift of
less (or more) than 9 0 ° produces an elliptical
oscilloscope pattern. The amount of phase
shift can be calculated from the oscilloscope
trace as shown in
Fig. 26.
NO AMPLITUDE DISTORTION
NO PHASE SHIFT
NO AMPLITUDE DISTORTION
PHASE SHIFT
AMPLITUDE DISTORTION
NO PHASE SHIFT
AMPLITUDE DISTORTION
PHASE SHIFT
180 OUT OF PHASE
9 0 OUT OF PHASE
Fig.
2 5
Typical phase measurement
oscilloscope displays
S I N E
0=%
W H E R E
0
= P H A S E
A N G L E
Fig. 26 Phase shift calculation
Frequency Measurement:
1. Connect the sine w a v e of known frequency to
the CH2 input of the oscilloscope and set the
S W E E P T I M E / D I V control to X - Y .
2. Connect the vertical input probe (CH1 input) to
the unknown frequency.
3. Adjust the C H 1 and C H 2 size controls for a
convenient, easy-to-read size of display.
4. The resulting, called Lissajous' pattern, shows
the ratio between the two frequencies (see
Fig. 27)
U N K N O W N F R E Q U E N C Y T O
V E R T I C A L I N P U T S T A N D A R D
F R E Q U E N C Y T O H O R I Z O N T A L
I N P U T
R A T I O O F
U N K N O W N
T O
S T A N D A R D
1 : 1
1-1/2
: 1
6 : 1
Fig. 27 Lissajous' waveforms used for
frequency measurement
24
1/2
: 1
Содержание CS-1566A
Страница 5: ...CONTROLS ON PANELS FRONT PANEL Fig 1 REAR PANEL Fig 2 5...
Страница 33: ...SCHEMATIC DIAGRAM CS 1566A 33...
