The Op-Amp circuit shown above represents a

Consider the Schmitt trigger circuit shown below.

A triangular wave which goes from -12V to 12V is applied to the inverting input of the OP-AMP. Assume that the output of the OP-AMP swings from +15V to -15V. The voltage at the non-inverting input switches between.

Consider the amplitude modulated (AM) signal $$A_c\cos\omega_ct\;+\;2\cos\omega_mt\;\cos\omega_ct$$. For demodulating the signal using envelope detector, the minimum value of A_c should be

The signal $$\cos\;\omega_ct\;+\;0.5\;\cos\;\omega_mt\;s\mathrm{in}\;\omega_ct$$ is