Re: IR detector system, biasing of photo diode

On 10/29/2024 4:20 AM, Liz Tuddenham wrote:

Klaus Vestergaard Kragelund <klauskvik@hotmail.com> wrote:
 [...]

>
If the chirp arrives at the same time at each mike, the robot is on the
right path, If one is delayed, the robot eases into the that direction

 If one of  the chirps has been reflected from a distant hard surface the
long delay could interfere with the next pulse.  Something like that
happened to an early-warning radar sytem when the moon rose and
reflected long-delayed pulses.
 A slow pulse rate or a variable one would overcome this.

ISTR Polaroid's ultrasonic ranging kit; the transducer was driven
with pulses in a fixed pattern at four distinct frequencies.
This helped the receiver determine the "envelope" for a single burst.
In LORAN, the carrier was modulated with a specific envelope
(as well as a pulse code pattern) to let the receiver identify
a specific reference point on the carrier.  (because multiple
signal sources could be present in a given geographical area)