Consider the signal $$s\left(t\right)\;=\;m\left(t\right)\;\cos\left(2{\mathrm{πf}}_\mathrm c\mathrm t\right)\;+\widehat m\left(t\right)\;\sin\left(2\mathrm\pi\;{\mathrm f}_\mathrm c\mathrm t\right)$$ where $$\widehat m\left(t\right)\;$$ denotes the Hilbert transform of m(t) and the bandwidth of m(t) is very small compared to f_c. The signal s(t) is a

Consider an FM signal $$f\left(t\right)\;=\;\cos\left[2{\mathrm{πf}}_\mathrm c\mathrm t\;+\;{\mathrm\beta}_1\sin\;2{\mathrm{πf}}_1\mathrm t\;+\;{\mathrm\beta}_2\sin\;2{\mathrm{πf}}_2\mathrm t\right]$$ . The maximum deviation of the instantaneous frequency from the carrier frequency f_c is

Consider an angle modulated signal x(t) = 6cos[2$$\mathrm\pi$$x10⁶ t+2sin(8000$$\mathrm\pi$$t) + 4cos(8000$$\mathrm\pi$$t)] V. The average power of x(t) is.

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