Principles of Communication Reviewer PDF

***PRINCIPLES OF COMMUNICATIONR REVIEWER*** ***Modulation** -- is the process of converting raw message data into digital signals or waves over a modulator top optimize transmission.* ***Carrier Signal** -- is the steady waveform in terms of amplitude(height) and frequency(speed).* ***Modulating...

***PRINCIPLES OF COMMUNICATIONR REVIEWER*** ***Modulation** -- is the process of converting raw message data into digital signals or waves over a modulator top optimize transmission.* ***Carrier Signal** -- is the steady waveform in terms of amplitude(height) and frequency(speed).* ***Modulating Signal --** is the message that must be transmitted.* ***Modulated Signal --** is the output signal after the process.* Amplitude Modulation - **AM (Amplitude Modulation):** The **amplitude** of the carrier signal changes based on the message, but the frequency and phase remain the same. - **Envelope:** An imaginary line connects positive and negative peaks of the carrier waveform. - **Time Domain Signals:** are voltage or current variations that occur over time and are displayed on an oscilloscope screen. - **Sidebands:** are the sum and difference of the carrier and modulating frequencies. - **Frequency Domain:** Where the horizontal axis represents frequency, and the vertical axis represents the signals magnitude (amplitude/ voltage,current,power). - Modulation Index: Referred as the degree of modulation or modulating factor or coefficient. - To get the percentage of modulation, multiply the modulation index by **100.** - **Vmax: The peak value** - **Vmin: is the lowest** Formulas: 𝑓𝑈𝑆𝐵 = 𝑓𝑐 + 𝑓m 𝑓𝐿𝑆𝐵 = 𝑓𝑐 -- 𝑓m Total bandwidth: 𝐵𝑊 = 𝑓𝑈𝑆𝐵 − 𝑓𝐿𝑆𝐵 or 𝐵𝑊 = 2𝑓m Modulation Index M = Vm/Vc Frequency Modulation - **FM (Frequency Modulation):** The **frequency** of the carrier signal changes based on the message, but the amplitude and phase remain the same. - Frequency Deviation: It is the amount of change in the carrier frequency caused by modulating signal. Note(The Maximum Frequency deviation happens at the maximum amplitude of modulating signal. Formula: 𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝐷𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 = 𝑐𝑎𝑟𝑟𝑖𝑒𝑟 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 + 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐y 𝑀𝑖𝑛𝑖𝑚𝑢𝑛 𝐷𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 = 𝑐𝑎𝑟𝑟𝑖𝑒𝑟 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 − 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐y 𝑓𝑑 = 𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 − 𝑚𝑖𝑛𝑖𝑚𝑢𝑚 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 Frequency- Shift Keying (FSK) -In FM, a series of rectangular waves, such as serial binary data, **can represent the modulating signal**. This kind of modulating signal **will only have two amplitudes and will also make the carrier frequency have two values (1 and 0)**, such as this modulating signal: -The amount of shift depends on the amplitude of the binary signal. -Frequency of the carrier changes Phase Modulation - **PM (Phase Modulation):** The **phase** of the carrier signal changes based on the message, but the amplitude and frequency remain the same. - **Phase Shift Keying:** The shift happens whether the signal is positive or negative. - Phase of the carrier changes