VISHAY

TSOP69..

Document Number 84687

Rev. 1.0, 01-Mar-05

Vishay Semiconductors

www.vishay.com

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Suitable Data Format

The circuit of the TSOP69.. is designed in that way

that unexpected output pulses due to noise or distur-

bance signals are avoided. A bandpass filter, a limiter

stage, an integrator stage and an automatic gain con-

trol are used to suppress such disturbances.

The distinguishing mark between data signal and dis-

turbance signal are carrier frequency, burst length

and duty cycle.

The data signal should fulfill the following conditions:

• Carrier frequency should be close to center fre-

quency of the bandpass (e.g. 38 kHz).

• Burst length should be 6 cycles/burst or longer.

• After each burst which is between 6 cycles and 120

cycles a gap time of at least 10 cycles is necessary.

• For each burst which is longer than 3.2 ms a corre-

sponding gap time is necessary at some time in the

data stream. This gap time should have at least same

length as the burst.

• Up to 2200 short bursts per second can be received

continuously.

Some examples for suitable data format are: NEC

Code, Toshiba Micom Format, Sharp Code, RC5

Code, RC6 Code, RCMM Code, R-2000 Code,

RECS-80 Code.

When a disturbance signal is applied to the TSOP69..

it can still receive the data signal. However the sensi-

tivity is reduced to that level that no unexpected

pulses will occur.

Some examples for such disturbance signals which

are suppressed by the TSOP69.. are:

• DC light (e.g. from tungsten bulb or sunlight)

• Continuous signal at 38 kHz or at any other fre-

quency

• Signals from fluorescent lamps with electronic bal-

lasts with various kinds of modulation

(see examples in Figure 13 and Figure 14).

Figure 13. IR Signal from Fluorescent Lamp with low Modulation

Figure 14. IR Signal from a Fluorescent Lamp with Spikes

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5

10

15

20

Time ( ms )

16920

IR Signal from fluorescent

lamp with low modulation

Time(ms)

18659

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1

2

3

4

5

6

7

8

9

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