The circuit in the figure employs positive Feedback and is intended to generate sinusoidal oscillation. If at a frequency f$$_0$$, B(f)= $${{\Delta {V_f}(f)} \over {{V_0}(f)}} = {1 \over 6}\,\,\angle {0^0}$$ then to sustain oscillation at this frequency.

In a negative feedback amplifier using voltage - Series (i.e., voltage - sampling, series mixing) feedback

If the variance $$\sigma _d^2$$ of d(n) = x(n - 1) is one-tenth the variance $$\sigma _x^2$$ of a stationary zero-mean discrete-time signal x(n), then the normalized autocorrelation function $${R_{xx}}\,(k)\,/\,\,\sigma _x^2\,at\,\,k\,\, = \,1$$ is

For a bit-rate of 8 kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are