
Page 4
June 1999 TOKO, Inc.
TK15220
TOTAL HARMONIC DISTORTION (FIGURE 4)
Use the lower distortion oscillator for this measurement
because the distortion of the TK15220 is very low.
1) Pin 4 is in the open condition, or high level.
2) Connect a distortion analyzer to Pin 2.
3) Input the sine wave (1 kHz, 1 Vrms) to Pin 1.
4) Measure the distortion of Pin 2. This value is the
distortion of Ach.
5) Next connect Pin 4 to the V
, or high level.
6) Input the same sine wave to Pin 3.
7) Measure in the same way. This value is the distortion
of Bch.
VOLTAGE GAIN (FIGURE 5)
This is the output level against the input level.
1) Pin 4 is in the open condition, or low level.
2) Connect AC volt meters to Pin 1 and Pin 3.
(Using the same type meter is best)
3) Input a sine wave (1 kHz) to Pin 1 (f = optional up to max.
20 kHz, 1 Vrms).
4) Measure the level of Pin 1 and name this V1.
5) Measure the level of Pin 2 and name this V2.
6) Calculate Gain = 20 Log (( |V2 - V1| )/V1)
V1<V2 = + Gain, V1>V2 = - Gain
This value is the voltage gain of Ach.
7) Next, connect Pin 4 to the GND, or high level.
8) Input the same sine wave to Pin 3.
9) Measure and calculate in the same way.
This value is the voltage gain of Bch.
TEST CIRCUITS AND METHODS (CONT.)
VCC
+
+
~
THD
Figure 4
VCC
+
+
~
V
V
V1
V2
Figure 5
MAXIMUM INPUT LEVEL (FIGURE 6)
This measurement measures at the output side.
1) Pin 4 is in the open condition, or low level.
2) Connect a distortion analyzer and an AC volt meter to
Pin 2.
3) Input a sine wave (1 kHz) to Pin 1 and elevate the voltage
from 0 V gradually until the distortion gets to 0.1% at Pin
2.
4) When the distortion amounts to 0.1%, stop elevating and
measure the AC level of Pin 2.
This value is the maximum input level of Ach.
5) Next, connect Pin 4 to the V
, or high level.
6) Input the same sine wave to Pin 2.
7) Measure in the same way.
This value is the maximum input level of Bch.
VCC
+
+
~
V
THD
Figure 6