A scheme shown below is to generate a wide band FM modulate signal.

Narrow band FM has carrier frequency = 400 KHz Deviation ratio = 0.2 Wide band FM has carrier frequency = 100 MHz Deviation ratio = 6 Local oscillator frequencies can be

The characteristic equation of a control system is given as s^{4} + 4s^{3} + 4s^{2} + 3s + K = 0. What is the value of K for which this system is marginally stable?