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From: gdouglas@gulf.uvic.ca (Gerry Douglas)
Subject: Question about Sharp's GP1U52X IR Det.
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Date: Sun, 25 Jun 1995 11:55:41 LOCAL

In the book "Mobil Robots - Inspiration and Implementation" the author says on 
page 108,

    "The Sharp detector responds to a carrier frequency of 40Khz.  A 
40Khz frequency means the LED is blinking on and off with  a period of 25 
microseconds (us).  According to the device specifications, this signal 
should then be modulated at a lower frequency.  The blinking should be on for 
600us and then off for 600 us.  Figure 5.13 gives the timing diagram and 
protocol for this emitter-detector pair."

I have experimeted with the device on the bench and it appears that the 
detector will respond to an UNMODULATED 40Khz IR signal.  Can anyone tell me 
what the author is getting at when he/she says that the 40Khz carrier must be 
modulated.
I would also be greatful if someone could tell me where to get a spec. sheet 
for this device.

Thanks in advance,
Gerry Douglas.
