Currently the system operates 2 channels at 2 frequencies, 50 kHz and
55 kHz. This allows for 2 objects to be detected over the board, and
their movements potentially to be tracked. The control box circuit will
need to produce these two signals. A number of different oscillator
designs are being considered.
The 4 corner voltages are read from the backgammon sensor and consist
of a sum of the 50 kHz and 55 kHz signals. These signals must be separated
into 2 channels in order to provide meaningful position readings of
each of the objects being detected. A number of active band-pass filter
designs are being looked at. There must be enough attenuation of the
other unwanted channel in each filter so as to minimize position measurement
error. Digital filtering could potentially be an option as well, however
latency issues come into play, making it an unlikely that this method
will be chosen.