A hysteresis type $$TTL$$ inverter is used to realize an oscillator in the circuit shown in the figure.

If the lower and upper trigger level voltages are $$0.9$$ $$V$$ and $$1.7$$ $$V,$$ the period (in $$ms$$), for which output is LOW, is ____________.

The transfer characteristic of the Op-amp circuit shown in figure is

In the figure shown, assume the op-amp to be ideal. Which of the alternatives gives the correct Bode plots for the transfer function $${{{V_O}\left( \omega \right)} \over {{V_i}\left( \omega \right)}}?$$

Given the Op-amps in the figure of ideal, the output voltage $${V_0}$$ is