(Solved): 6. HART modem signal Background: HART sensors use frequency shift keying to transmit digital data o ...

6. HART modem signal Background: HART sensors use frequency shift keying to transmit digital data on pre-existing analog sensor lines. The frequency of the sinusoid is varied to send digital messages: $1.2\mathrm{kHz}$ is a digital $1$ and $2.2\mathrm{kHz}$ is a digital $1$. The figure ${}^{19}$ shows the measured signal on an oscilloscope. Problem: a) Is the sensor transmitting a digital $1$ or a digital $\mathbb{Q}$ ? b) Express the observed voltage as a cosine function of time $v(t)=\cos (\begin{array}{c}{}^{?}\\ +\end{array}+\text{ (Reading graphs is approximate, make }$ amplitude, offset, and frequencies accurate to $15\%$ and angles accurate to 15 degrees)