FM Modulation Explained PDF
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This document explains frequency modulation (FM), a method of modulating a carrier signal's frequency to convey information. The explanation is accompanied by graphical representations clarifying the relationships between input signals and the final output. It's suitable for undergraduate study in electronics and communications.
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## 3.5 FREQUENCY MODULATION Frequency modulation is a process in which the frequency of the carrier signal is made to vary in accordance with the instantaneous values of modulating signal while the amplitude of the carrier is held constant. The process of frequency modulation is shown in Fig. 3.11...
## 3.5 FREQUENCY MODULATION Frequency modulation is a process in which the frequency of the carrier signal is made to vary in accordance with the instantaneous values of modulating signal while the amplitude of the carrier is held constant. The process of frequency modulation is shown in Fig. 3.11. When the modulating signal is zero, the output frequency equals f (centre frequency). When the modulating signal reaches its positive peak the frequency of the modulated signal reaches a maximum. At negative peaks of the modulating signal, the frequency of the FM wave reaches a minimum. Thus, the process of frequency modulation makes the frequency of the carrier to deviate from its centre frequency (f) by an amount δ (frequency deviation). ### Message Signal The message signal is shown as a sine wave. It varies with time, and its frequency is the modulating frequency. ### Carrier Signal The carrier signal is shown as a high-frequency sine wave. The carrier frequency is constant. ### Frequency Modulated Signal The frequency modulated signal is shown as a sine wave. The frequency of the modulated signal changes with time. The three graphs show the relationship between the message signal, the carrier signal and the frequency modulated signal. ### Diagram Description: The image shows three graphs. The first graph shows the message signal. The second graph shows the carrier signal. The third graph shows the frequency modulated signal. Each graph shows the signal with time on the x-axis and amplitude on the y-axis. The message signal is a sine wave with a relatively low frequency. The carrier signal is a sine wave with a relatively high frequency and constant amplitude. The frequency modulated signal is a sine wave with a frequency that varies with time. The frequency of the frequency modulated signal varies in response to changes in the message signal. When the message signal is at its peak, the frequency of the frequency modulated signal is highest. When the message signal is at its trough, the frequency of the frequency modulated signal is lowest.
