Amplitude Modulation Concepts

What Is Amplitude Modulation? As the name suggests, in AM, the information signal varies the amplitude of the carrier sine wave. The instantaneous value of the carrier amplitude changes in accordance with the amplitude and frequency variations of the modulating signal. Fig. 3-1 shows a  single frequency sine wave intelligence signal modulating a higher-frequency carrier. The carrier … Read more


The modulation index should be a number between 0 and 1. If the amplitude of the modulating voltage is higher than the carrier voltage, m will be greater than 1, causing distortion of the modulated waveform. If the distortion is great enough, the intelligence signal becomes unintelligible. Distortion of voice transmissions produces garbled, harsh, or … Read more

Sideband and the Frequency Domain

What is Sideband? Whenever a carrier is modulated by an information signal, new signals at different frequencies are generated as part of the process. These new frequencies, which are called side frequencies, or sidebands, occur in the frequency spectrum directly above and directly below the carrier frequency. More specifically, the side bands occur at frequencies … Read more

Amplitude Modulation ( AM ) Power

Explanation of Amplitude Modulation Power? In radio transmission, the amplitude modulation signal is amplified by a power amplifier and fed to the antenna with a characteristic impedance that is ideally, but not necessarily, almost pure resistance. The AM signal is really a composite of several signal voltages, namely, the carrier and the two sidebands, and … Read more

Single Sideband (SSB) | Double Side Band Modulation

What is Single SideBand ? In amplitude modulation, two-thirds of the transmitted power is in the carrier, which itself conveys no information. The real information is contained within the side bands. One way to improve the efficiency of amplitude modulation is to suppress the carrier and eliminate one side band. The result is a single-sideband … Read more

Amplitude Modulators | Low Level AM | High Level AM

What is Amplitude Modulators? Amplitude modulators are generally one of two types: low level or high level. Low-level modulators generate AM with small signals and thus must be amplified considerably if they are to be transmitted. High-level modulators produce AM at high power levels, usually in the final amplifier stage of a transmitter. Although the … Read more

Amplitude Demodulator | Diode | Crystal Radio | Synchronous Detection

What is Amplitude Demodulator Amplitude Demodulator, or detectors, are circuits that accept modulated signals and recover the original modulating information. The Amplitude demodulator circuit is the key circuit in any radio receiver. In fact, Amplitude demodulator circuits can be used alone as simple radio receivers. Diode Detectors The simplest and most widely used amplitude demodulator … Read more

Balanced Modulator | Applications for 1496/1596 ICs

What is Balanced Modulator? A balanced modulator is a circuit that generates a DSB signal, suppressing the carrier and leaving only the sum and difference frequencies at the output. The output of a balanced modulator can be further processed by filters or phase-shifting circuitry to eliminate one of the sidebands, resulting in an SSB signal. … Read more