5 The circuit shown in Figure P8.55 is an active filter with R = 4.7 k2 C = 100 pF R2 = 68 k2 R1 = 220 k2 Determine the cutoff frequencies and the magnitude of the voltage frequency response function at very low and at very high frequencies. R1 RV.(ja) ww +2

3 The op-amp circult shown in Figure P8.53 is used as a filter. C = 0.1 µF RL = 333 2 R = 1.8 k2 R2 = 8.2 k2 Determine a. Whether the circuit is a low- or high-pass filter. b. The gain V./ Vs in decibels in the passband, that is, at the frequencies being passed by the filter. c. The cutoff frequency. R2 R1

7-22 Abasehand signal with frequency components from near de to 15 kHz frequency modulates a 200-kHz carrier, and the frequency deviation is +3 kHz. The signal is applied as the input to a cascade of two frequency triplers and one frequency doubler. Determine the output (a) center fre- quency, (b) frequency deviation, and (c) deviation ratio.

CR active filters find extensive use in communications and instrumentation measurements. a) By considering how the capacitor impedance in Figure 1 varies with frequency, explain if the circuit in Figure 1 acts as a low-pass or high-pass filter. p) Derive the closed-loop gain for the case of very high frequencies. c) Draw a graph that shows the frequency response of the CR active high-pass filter. The y-axis should correspond to gain in dBs and the x-axis to frequency. Make sure that you clearly indicate the 3 dB point and the equation that describes the relationship between w and CinRin at the cut-off frequency. Cin Rin A Vin Vout Figure 1