Attended: Mengyuan, Creighton, Scott

• Updates:
• To Do:

• Updates:
  • Right before the CDR, made the realization that instead of going through the trouble of offsetting the received signal and using a threshold detector, we could keep the received signal centered at 0V and use a zero-crossing detector. This will simplify our design by quite a bit (we would forego the Schmitt trigger, threshold detectors, and possibly the amplifier). Also, the zero-crossing detector is relatively simple to build.
  • Tested zero-crossing detector with oscilloscope:
    • Initially tried to do it with an op-amp but we were limited by the slew rate. When we did find an op-amp with a high enough slew rate, the rise time was relatively slow (see below).
    • 
    • We then decided to test it with our voltage comparator set at 0V, and it gave us much better results (see below).
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  • Delay 12.5us using nops:
    • Not very reliable, a better approach would be to try and modify the timer's prescaler and initial value to achieve a 12.5us trigger.
  • Receiver response when sending just 1 pulse:
    • Sending just a single pulse through the emitter still causes a relatively long received signal. Also, there is an audible frequency (~3kHz) coming from the emitter
    • 
  • DigitalWrite() vs. fastDigitalWrite():
    • This is probably the time between the function call and the pin change, rather than the actual rise time, which is a physical property.
    • digitalWrite() rise ~ 22ns
    • digitalWriteFast() rise ~22ns
  • Delay vs. Timer:
    • The Timer was more precise and accurate whereas the delay had some relatively large fluctuations ~8%.
• TO Do: