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

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

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