AM Modulation - Diode

519

10:00:39

AM modulation is the process of encoding a information frequency into a carrier frequency.  By adding then multiplying the two together, the carrier peak voltage is adjusted by the amplitude of the information signal.

This circuit uses a biased diode to provide nonlinear modulation.  An LC circuit tuned to the carrier afterwards both adds the bottom half to the rectified signal, as well as acts as a bandpass filter to filter out the harmonics (Vm, 2 Vm and 2Vc) that are produced from the modulation.

The drawback to using a diode as a modulator is because of its low forward bias, this can only be used on small signals in the millivolt range.

published 11 years ago

Secuture

11 years ago

I build plenty diode am and fm modultors here based on biasing diode by dc signall connected in series with them or trough complicated bridge networks and shaping desired nonlinearity by changing diode emission coefficient and reverse saturation current . I use those as varistors to perform remote voltage controll over various functions of oscillator like changing it's frequency duty cycle or amplitude.so i asume that diode modulators do not have biger secrets for me. ................But i completely cant' get break through ur language and catch what is come on and what ya need and where :-) so please have mercy upon people whose "science english" was not in paid english course cuz nobody knows how to explain meaning of this words at all.

hurz

11 years ago

good finetuned real working example. Keep on teaching

hydraulicguru

11 years ago

Great explanation of the circuit, thanks.

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.