(IV) A specialist sensor is being used to detect the pollution being emitted from an engine. The true signal is in the range of 30-50mV DC but is being affected by 800HZ AC noise from the electronic engine controller. Design a modular system consisting of a filter (that removes the noise) and an op-amp based amplifier (that increases the signal to a range of 3-5V DC)

Figure 3 shows a Hartley oscillator. Assume that the op-amp employed in the figure is an ideal op-amp, and R1= 20 kΩ, R2 = 60 kΩ, L1=10 mH.  b) State the Barkhausen criterion for sustained oscillation.c) Explain briefly how the phase shift requirement for sustained oscillation ismet in the circuit of Figure 3.d) The feedback ratio and oscillation frequency of Figure 3 are givenrespectively by, B = -L2/L1 and w0 = 1 / sqrt(L1 +L2)C Determine the values of C and L2 in order for the circuit to oscillate at a frequency of 200 Hz.

ii. The slew rate of an op-amp is defined as the: (i) Maximum rate of change of output voltage with time(ii) Minimum rate of change of output voltage with time(iii) Moderate rate of change of output voltage with time(iv) None of the above