May 1999 TOKO, Inc.

Page 5

TK15321

TEST CIRCUITS AND METHODS (CONT.)

RESIDUAL NOISE (FIGURE 7)

This value is not S/N ratio. This is a noise which occurs from

the device itself.

1) Pin 5 is the open condition, or high level.

2) Connect an AC volt meter to Pin 3.

3) Connect a capacitor from Pin 4 to GND.

4) Measure AC voltage of Pin 3. This value is the noise of

1-Ach. If the influence of noise from outside exists, use

optional filters.

5) Next, connect Pin 5 to the GND, or low level.

6) Connect to GND through a capacitor from Pin 2.

7) Measure in the same way.

This value is the noise level of 1-Bch.

VCC

Cont.

+

+

Figure 5

MAXIMUM INPUT LEVEL (FIGURE 6)

This measurement measures at output side.

1) Pin 5 is in the open condition, or high level.

2) Connect a distortion analyzer and an AC volt meter to

Pin 3.

3) Input a sine wave (1 kHz) to Pin 4 and elevate the voltage

from 0 V gradually until the distortion gets to 0.1%.

4) When the distortion amounts to 0.1%, stop elevating and

measure the AC level of Pin 3.

This value is the maximum input level of 1-Ach.

5) Next, connect Pin 5 to the GND, or low level.

6) Input the same sine wave to Pin 2.

7) Measure in the same way.

This value is the maximum input level of 1-Bch.

VCC

Cont.

+

+

Figure 6