I have a analog signal that is converted into a discrete-time signal with an ideal A/D converter with a sampling frequency $fs$. The bandwidth of the signal of interest is $1 kHz$. The resulting signal $x[n] = x_a(nT_s)$ is then processed with a discrete-time system that is described by the difference equation:
$$y[n] = x[n]+ax[n-1]+bx[n-2]$$
The filtered signal, $y[n]$, is then converted back into an analog signal using an ideal D/A converter. I need to determine values for $fs$, $a$ and $b$ in order to remove a $60Hz$ interference that has a signal in the form: $i_a(t) = Asin(120 \pi t)$
By Nyquist, I know that the value of $fs$ needs to be greater than $2000Hz$, however, I don't know how to determine $a$ and $b$. Any thoughts?