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Pengertian Modulasi dan Jenis-jenisnya
Pengertian Modulasi dan Jenis-jenisnya – Saat ini, banyak informasi baik yang berupa informasi analog maupun informasi digital yang dikomunikasikan melalui teknologi nirkabel (wireless) yang pada dasarnya adalah menggunakan frekuensi radio sebagai media transmisinya. Salah satu aspek dasar penting dalam sistem komunikasi radio ini adalah Modulasi, yaitu cara dimana informasi tersebut ditumpangkan pada gelombang radio yang berfungsi sebagai pembawanya.
Gelombang Pembawa biasanya berbentuk gelombang sinus yang berfrekuensi tinggi. Tiga parameter penting pada suatu gelombang sinus diantaranya adalah Amplitudo, Frekuensi dan Fasa. Parameter-parameter tersebut dapat dimodifikasi sesuai dengan sinyal informasinya sehingga membentuk sinyal yang termodulasi.
Secara definisi, Modulasi dapat diartikan sebagai proses perubahansuatu gelombang periodik sehingga menjadi suatu sinyal yang mampu membawa suatu informasi. Jadi untuk dapat mengirimkan suatu informasi dari suatu perangkat ke perangkat lainnya yang menggunakan Teknologi Frekuensi Radio, informasi tersebut harus dimodulasi terlebih dahulu sebelum dipancarkan. Rangkaian yang berfungsi sebagai Modulasi disebut dengan Modulator.
Contoh perangkat atau peralatan yang memerlukan rangkaian modulasi diantaranya seperti Pemancar Radio, Telepon Selular (Ponsel), Pemancar Televisi dan Modem.
Jenis-jenis Modulasi
Jenis Modulasi dapat dikelompokkan berdasarkan Sinyal informasi akan dikirimnya yaitu sinyal Analog dan sinyal Digital. Berdasarkan jenis sinyal informasi tersebut, maka Modulasi dapat dibagi menjadi 2 jenis yaitu Modulasi Analog dan Modulasi Digital.
1. Modulasi Analog
Pada dasarnya, Sinyal Analog adalah sinyal data yang berbentuk gelombang kontinyu (terus-menerus). Teknik Modulasi untuk sinyal informasi Analog dapat dibagi menjadi 3 jenis berdasarkan parameter suatu gelombang sinus. Setiap jenis modulasi memiliki kelemahan dan kelebihannya. Berikut ini adalah tiga jenis Modulasi Analog yang sering digunakan dalam sistem komunikasi Radio Analog.
1.1. Amplitude Modulation (AM)
Seperti namanya, Amplitude Modulation (AM) atau Modulasi Amplitudo adalah salah satu teknik Modulasi yang proses pemodulasian sinyal frekuensi rendah (sinyal informasi) pada frekuensi tinggi dengan mengubah Amplitudo gelombang frekuensi tinggi (frekuensi pembawa) tanpa mengubah frekuensinya. Jadi pada Modulasi Amplitudo ini, sinyal pembawanya berubah-ubah secara proporsional terhadap Amplitudo sinyal pemodulasi sedangkan frekuensi tetap selama proses modulasi.
1.2. Frequency Modulation (FM)
Frequency Modulation (FM) atau Modulasi Frekuensi adalah teknik pengiriman informasi yang berbentuk frekuensi rendah dengan cara memodulasi frekuensi gelombang pembawa yang berfrekuensi tinggi. Jadi pada Modulasi Frekuensi ini, sinyal informasi akan mengubah frekuensi gelombang pembawanya sedangkan Amplitudonya tetap selama proses modulasi.
1.3. Phase Modulation (PM)
Yang dimaksud dengan Fasa atau Phase adalah besar sudut dari sinyal analog pada saat tertentu. Phase Modulation (PM) atau Modulasi Fasa merupakan suatu teknik modulasi yang merepresentasikan informasi sebagai variasi fasa (phase) dari sinyal pembawanya. Pada Modulasi Fasa ini, sinyal informasi mengubah fasa gelombang pembawanya sedangkan Amplitudo gelombang pembawanya tetap (tidak berubah). Teknik modulasi Fasa ini jarang digunakan karena memerlukan perangkat penerima yang lebih kompleks.
Berikut dibawah ini adalah bentuk gelombang Modulasi Amplitudo (AM), Modulasi Frekuensi (FM) dan Modulasi Fasa (PM)
2. Modulasi Digital
Sinyal Digital adalah sinyal data dalam bentuk pulsa dan hanya memiliki dua kondisi yaitu 0 (ON) dan 1 (OFF). Sinyal Digital ini memiliki beberapa kelebihan yaitu tidak mudah terpengaruh oleh derau, proses informasinya mudah, cepat dan akurat. Sama seperti sinyal analog, untuk mengirimkan sinyal digital ini dari suatu perangkat elektronik ke perangkat elektronik lainnya dengan menggunakan teknologi nirkabel atau Wireless (Radio Frekuensi) juga diperlukan proses pemodulasian yang dinamakan dengan Modulasi Digital. Yang dimaksud dengan Modulasi Digital adalah proses penumpangan sinyal digital ke dalam sinyal pembawanya (Carrier Signal). Modulasi Digital pada dasarnya adalah proses pemodifikasian sifat dan karakteristik gelombang pembawa sehingga bentuk hasil gelombang pembawanya memiliki ciri-ciri bit (0 atau 1).
Modulasi Digital terdiri dari tiga jenis dasar yaitu Amplitudo Shift Keying (ASK), Freqency Shift Keying (FSK) dan Phase Shift Keying (PSK). Namun seiring dengan perkembangan teknologi saat ini, muncul teknik-teknik modulasi digital yang merupakan kombinasi dari ketiga jenis dasar modulasi tersebut seperti APK (Amplitude Phase Keying), QAM (Quadrature Amplitude Modulation) dan lain sebagainya.
2.1. Amplitude Shift Keying (ASK)
Amplitudo Shift Keying (ASK) adalah salah satu bentuk modulasi yang gelombang pembawanya dimodulasi berdasarkan Amplitudo sinyal informasi digitalnya. Dalam sistem modulasi ASK, simbol biner 1 direpresentasikan dengan suatu ketinggian Amplitudo tertentu pada gelombang pembawanya. Jika sinyalnya berupa 1, maka sinyal pembawa tersebut akan dikirimkan. Jika tidak, maka sinyal 0 yang akan dikirimkan. Dengan kata lain, munculnya frekuensi gelombang pembawa tergantung pada ada atau tidaknya sinyal digital.
2.2. Frequency Shift Keying (FSK)
Frequency Shift Keying (FSK) adalah bentuk modulasi digital yang gelombang pembawanya dimodulasi berdasarkan pergeseran Frekuensi. Dalam sistem modulasi FSK (Frequency Shift Keying ), maka simbol 1 dan 0 ditransmisikan Secara berbeda antara satu sama lain dalam satu atau dua buah sinyal sinusoidal yang berbeda besar frekuensinya.
2.3. Phase Shift Keying (PSK)
Phase Shift Keying (PSK) merupakan bentuk modulasi yang proses pemodulasian menggunakan cara penggeseran Fasa(Phase). Pada sistem modulasi Phase Shift Keying (PSK), sinyal gelombang pembawa sinusoidal dengan amplitudo dan frekuensi yang dapat digunakan untuk menyatakan sinyal biner "1" dan "0", tetapi untuk sinyal "0" fasa gelombang pembawa tersebut digeser 180°.
Berikut dibawah ini adalah bentuk gelombang Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK) dan Phase Shift Keying (PSK).
Definition of Modulation and its Types
Dickson Kho Electronics Theory
Understanding Modulation and its Types - At present, a lot of information both in the form of analog information and digital information that is communicated through wireless technology (wireless) which is basically using radio frequency as a transmission media. One important basic aspect in this radio communication system is Modulation, which is the way in which the information is superimposed on radio waves that function as carriers.
Carrier Waves are usually in the form of high frequency sine waves. Three important parameters in a sine wave include Amplitude, Frequency and Phase. These parameters can be modified according to the information signal to form a modulated signal.
By definition, modulation can be interpreted as the process of changing a periodic wave so that it becomes a signal capable of carrying information. So to be able to send information from one device to another that uses Radio Frequency Technology, the information must be modulated before being transmitted. The circuit that functions as modulation is called a modulator.
Examples of devices or equipment that require modulation circuits include Radio Transmitters, Cell Phones (Television), Television Transmitters and Modems.
Types of Modulation
Modulation types can be grouped based on the information signal they will send, namely Analog signal and Digital signal. Based on the type of information signal, the modulation can be divided into 2 types namely Analog Modulation and Digital Modulation.
1. Analog Modulation
Basically, an Analog Signal is a data signal in the form of a continuous wave (continuous). Modulation techniques for Analog information signals can be divided into 3 types based on the parameters of a sine wave. Each type of modulation has advantages and disadvantages. The following are three types of Analog Modulation that are often used in Analog Radio communication systems.
1.1. Amplitude Modulation (AM)
As the name suggests, Amplitude Modulation (AM) is one of the modulation techniques that modulates the low frequency signal (information signal) at high frequency by changing the amplitude of the high frequency wave (carrier frequency) without changing its frequency. So in this amplitude modulation, the carrier signal changes proportionally to the amplitude of the modulating signal while the frequency remains during the modulation process.
1.2. Frequency Modulation (FM)
Frequency Modulation (FM) is a low frequency information transmission technique by modulating the frequency of a high-frequency carrier wave. So in this Frequency Modulation, the information signal will change the frequency of the carrier wave while the amplitude remains during the modulation process.
1.3. Phase Modulation (PM)
What is meant by Phase or Phase is the angle of the analog signal at a particular moment. Phase Modulation (PM) or Phase Modulation is a modulation technique that represents information as phase variations of the carrier signal. In this Phase Modulation, the information signal changes the carrier wave phase while the carrier wave amplitude remains (unchanged). This phase modulation technique is rarely used because it requires a more complex receiver device.
Following below are the waveforms of Amplitude Modulation (AM), Frequency Modulation (FM) and Phase Modulation (PM).
Definition of Analog Modulation and its Types
2. Digital Modulation
Digital signal is a data signal in the form of pulses and has only two conditions namely 0 (ON) and 1 (OFF). This digital signal has several advantages, namely not easily influenced by noise, the information process is easy, fast and accurate. Just like analog signals, to transmit this digital signal from an electronic device to other electronic devices using wireless technology or Wireless (Radio Frequency) also requires a modulation process called Digital Modulation. What is meant by Digital Modulation is the process of laying down a digital signal into its carrier signal (Carrier Signal). Digital modulation is basically the process of modifying the nature and characteristics of a carrier wave so that the shape of the carrier wave has the characteristics of bits (0 or 1).
Digital modulation consists of three basic types namely Amplitude Shift Keying (ASK), Freqency Shift Keying (FSK) and Phase Shift Keying (PSK). But along with current technological developments, emerging digital modulation techniques are a combination of the three basic types of modulation such as APK (Amplitude Phase Keying), QAM (Quadrature Amplitude Modulation) and so forth.
Dickson Kho Electronics Theory
Understanding Modulation and its Types - At present, a lot of information both in the form of analog information and digital information that is communicated through wireless technology (wireless) which is basically using radio frequency as a transmission media. One important basic aspect in this radio communication system is Modulation, which is the way in which the information is superimposed on radio waves that function as carriers.
Carrier Waves are usually in the form of high frequency sine waves. Three important parameters in a sine wave include Amplitude, Frequency and Phase. These parameters can be modified according to the information signal to form a modulated signal.
By definition, modulation can be interpreted as the process of changing a periodic wave so that it becomes a signal capable of carrying information. So to be able to send information from one device to another that uses Radio Frequency Technology, the information must be modulated before being transmitted. The circuit that functions as modulation is called a modulator.
Examples of devices or equipment that require modulation circuits include Radio Transmitters, Cell Phones (Television), Television Transmitters and Modems.
Types of Modulation
Modulation types can be grouped based on the information signal they will send, namely Analog signal and Digital signal. Based on the type of information signal, the modulation can be divided into 2 types namely Analog Modulation and Digital Modulation.
1. Analog Modulation
Basically, an Analog Signal is a data signal in the form of a continuous wave (continuous). Modulation techniques for Analog information signals can be divided into 3 types based on the parameters of a sine wave. Each type of modulation has advantages and disadvantages. The following are three types of Analog Modulation that are often used in Analog Radio communication systems.
1.1. Amplitude Modulation (AM)
As the name suggests, Amplitude Modulation (AM) is one of the modulation techniques that modulates the low frequency signal (information signal) at high frequency by changing the amplitude of the high frequency wave (carrier frequency) without changing its frequency. So in this amplitude modulation, the carrier signal changes proportionally to the amplitude of the modulating signal while the frequency remains during the modulation process.
1.2. Frequency Modulation (FM)
Frequency Modulation (FM) is a low frequency information transmission technique by modulating the frequency of a high-frequency carrier wave. So in this Frequency Modulation, the information signal will change the frequency of the carrier wave while the amplitude remains during the modulation process.
1.3. Phase Modulation (PM)
What is meant by Phase or Phase is the angle of the analog signal at a particular moment. Phase Modulation (PM) or Phase Modulation is a modulation technique that represents information as phase variations of the carrier signal. In this Phase Modulation, the information signal changes the carrier wave phase while the carrier wave amplitude remains (unchanged). This phase modulation technique is rarely used because it requires a more complex receiver device.
Following below are the waveforms of Amplitude Modulation (AM), Frequency Modulation (FM) and Phase Modulation (PM).
Definition of Analog Modulation and its Types
2. Digital Modulation
Digital signal is a data signal in the form of pulses and has only two conditions namely 0 (ON) and 1 (OFF). This digital signal has several advantages, namely not easily influenced by noise, the information process is easy, fast and accurate. Just like analog signals, to transmit this digital signal from an electronic device to other electronic devices using wireless technology or Wireless (Radio Frequency) also requires a modulation process called Digital Modulation. What is meant by Digital Modulation is the process of laying down a digital signal into its carrier signal (Carrier Signal). Digital modulation is basically the process of modifying the nature and characteristics of a carrier wave so that the shape of the carrier wave has the characteristics of bits (0 or 1).
Digital modulation consists of three basic types namely Amplitude Shift Keying (ASK), Freqency Shift Keying (FSK) and Phase Shift Keying (PSK). But along with current technological developments, emerging digital modulation techniques are a combination of the three basic types of modulation such as APK (Amplitude Phase Keying), QAM (Quadrature Amplitude Modulation) and so forth.
2.1. Amplitude Shift Keying (ASK)
Amplitude Shift Keying (ASK) is a form of modulation in which the carrier wave is modulated based on the amplitude of the digital information signal. In the ASK modulation system, the binary symbol 1 is represented by a certain height of the amplitude of the carrier wave. If the signal is 1, then the carrier signal will be sent. If not, the signal 0 will be sent. In other words, the appearance of a carrier wave frequency depends on the presence or absence of a digital signal.
2.2. Frequency Shift Keying (FSK)
Frequency Shift Keying (FSK) is a form of digital modulation whose carrier waves are modulated based on frequency shifts. In the FSK (Frequency Shift Keying) modulation system, the symbols 1 and 0 are transmitted differently from one another in one or two sinusoidal signals with different frequency.
2.3. Phase Shift Keying (PSK)
Phase Shift Keying (PSK) is a form of modulation that the modulation process uses phase shifting (Phase). In the Phase Shift Keying (PSK) modulation system, sinusoidal carrier wave signals with amplitude and frequency can be used to express binary signals "1" and "0", but for the "0" signal the carrier wave phase is shifted 180 °.
Following below are the waveforms of Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK) and Phase Shift Keying (PSK).
Amplitude Shift Keying (ASK) is a form of modulation in which the carrier wave is modulated based on the amplitude of the digital information signal. In the ASK modulation system, the binary symbol 1 is represented by a certain height of the amplitude of the carrier wave. If the signal is 1, then the carrier signal will be sent. If not, the signal 0 will be sent. In other words, the appearance of a carrier wave frequency depends on the presence or absence of a digital signal.
2.2. Frequency Shift Keying (FSK)
Frequency Shift Keying (FSK) is a form of digital modulation whose carrier waves are modulated based on frequency shifts. In the FSK (Frequency Shift Keying) modulation system, the symbols 1 and 0 are transmitted differently from one another in one or two sinusoidal signals with different frequency.
2.3. Phase Shift Keying (PSK)
Phase Shift Keying (PSK) is a form of modulation that the modulation process uses phase shifting (Phase). In the Phase Shift Keying (PSK) modulation system, sinusoidal carrier wave signals with amplitude and frequency can be used to express binary signals "1" and "0", but for the "0" signal the carrier wave phase is shifted 180 °.
Following below are the waveforms of Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK) and Phase Shift Keying (PSK).
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