Introduction
In this article, we will discuss analog to analog conversion of the signal, and we will also discuss how we can achieve this conversion. It is the analog signal's description of analog data. Analog signal modulation is the process of transforming analog signals into digital signals. It's necessary since the sender's signal is low pass and might be in the same range as the receiver's. For example, each radio station has a low pass signal with a similar range. Different stations provide different signals; each low pass signal must be moved to a different frequency band range.
For example, the government gives each radio station a certain bandwidth. Each station's analog transmission is a low-pass signal with the same frequency range. The low-pass signals must be moved to various ranges to listen to different stations.
Converting from analog to analog may be done in three ways:
- Amplitude Modulation (AM)
- Frequency Modulation (FM)
- Phase Modulation (PM)
Recommended Topic, Basic Networking Commands and Personal Area Network
Amplitude Modulation
The carrier signal in AM transmission is modulated such that its amplitude fluctuates with the modulating signal's shifting amplitudes. The carrier's frequency and phase remain unchanged. Only the amplitude varies in response to changes in the data. The modulating signal, the carrier signal, and the resulting AM signal are shown in the diagram below.
Modulating Signal is represented by: m(t) = Amcos(2Ï€fmt)
Carrier Signal is represented by: c(t) = Accos(2Ï€fct)
Here Am and Ac represent the amplitudes of modulating and carrier waves while fm and fc represent the frequencies of the modulating and carrier waves respectively.
Therefore modulated signal can be represented as
M(t) = [Ac + Am cos(2Ï€fmt)] cos(2Ï€fct)
Bandwidth in the AM
The modulation provides a bandwidth that is double the modulating signal's bandwidth and spans a frequency centered on the carrier frequency. The signal components above and below the carrier frequency, on the other hand, contain the same data. As a result, some implementations delete one-half of the signals while halving the bandwidth.
The entire bandwidth needed for AM may be calculated using the audio signal's bandwidth:
Bandwidth of AM = 2*B
Here B is the bandwidth of the message signal i.e. equal to 2*fi
Where fi represents the frequency of the message signal.
Standard Bandwidth allocation for AM Radio
An audio signal's bandwidth (for voice and music) is normally 5 kHz. As a result, an AM radio station requires a 10kHz bandwidth. In actuality, the Federal Communications Commission (FCC) authorizes each AM station to broadcast at 10 kHz.
AM stations may use carrier frequencies ranging from 530 to 1700 kHz (1.7 MHz). Each station's carrier frequency must be separated by at least 10 kHz (one AM bandwidth) from those on either side to prevent interference. If one station utilizes a carrier frequency of 1100 kHz, the carrier frequency of the following station must be at least 1110 kHz.
Also see, Message Switching in Computer Networks.