A DSB-SC signal is to be generated with a carrier frequency fc = 1 MHz using a nonlinear device with the input-output characteristic V₀ = a₀v_i + a₁v_i³ where a0 and a1 are constants. The output of the nonlinear device can be filtered by an appropriate band-pass filter. Let v_i = A'_c cos (2$\pi$f'_c t) + m(t) where m(t) is the message signal. The value of f'_c (in MHz) is