[Ronja] new receiver design

[Gullik Webjörn]

> the receiver is working just fine ... with 220K feedback resistor SNR
> is enhanced dramatically ... the output of the TIA without an optical
> signal was reduced to 5mV p-p .. and the signal was about 400mV p-p ..
> the range was increased by a factor of 25% (without lenses ) .. i
> forgot to tell you that we have modified the transmitter as well . we
> used a cheap IR LED from vishay TSFF5210
> (http://www.vishay.com/docs/81090/tsff5210.pdf) .. this image
> illustrates the new configuration .. 

20 * log10( 400/5 ) = 38 dB. Do I understand correctly, at 2.5 m range
without lenses, you have 38 dB SNR ?? If so, then this is definitely
a large improvment. You should need 20 dB or so, the remaining 18
could be traded for range.

How are you measuring level, O-scope? If so, what is the rise time of
the signal after receiver? ( time from 10% to 90% ) 

> http://img100.imageshack.us/i/txfinal.jpg/
> 
> i need your comments please . 

So, essentially this is just a LED (and resistor ) change to "red"
ronja. The bandwidth of the HPWT and the TSFF5210 seems very similar.

Seems you are making progress....

Gullik