VISHAY

TSOP11..SK1

Document Number 82159

Rev. 2, 05-May-03

Vishay Semiconductors

www.vishay.com

5

Suitable Data Format

The circuit of the TSOP11..SK1 is designed in that

way that unexpected output pulses due to noise or

disturbance signals are avoided. A bandpass filter, an

integrator stage and an automatic gain control 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 70

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

• For each burst which is longer than 1.8 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

TSOP11..SK1 it can still receive the data signal. How-

ever the sensitivity is reduced to that level that no

unexpected pulses will occur.

Some examples for such disturbance signals which

are suppressed by the TSOP11..SK1 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-

last (an example of the signal modulation is in the fig-

ure below).

Figure 14. IR Signal from Fluorescent Lamp with low Modulation

0

5

10

15

20

Time ( ms )

16920

IR Signal from fluorescent

lamp with low modulation