A diode detector is used to detect an amplitude modulated wave of 60% modulation by using a condenser of capacity 250 pico farad in parallel with a load resistance of 100 kilo ohm. Find the maximum modulated frequency which could be detected by it.

Step-by-step solution

τ = RC = 1 0 0 × 1 0 3 × 2 5 0 × 1 0 - 1 2  sec = 2.5 × 1 0 7 × 1 0 -1 2  sec = 2.5 × 1 0 - 5  sec The higher frequency which can be detected with tolerable distortion is f = 1 2 π m a RC = 1 2 π × 0.6 × 2.5 × 1 0 - 5  Hz = 1 0 0 × 1 0 4 2 5 × 1.2 π    Hz = 4 1.2 π × 1 0 4  Hz =  10.61 kHz This condition is obtained by applying the condition that rate of decay of capacitor voltage must be equ