Modem used to converts digital signals to analog signals. It enables a computer to transmit data.
Digital -to- analog conversion (DAC), Process by which digital signals (which have a binary state) are converted to analog signals (which theoretically have an infinite number of states). For example, a modem converts computer digital data to analog audio-frequency signals that can be transmitted over telephone lines.
In electronics, a digital-to-analog converter (DAC, D/A, D–A, D2A, or D-to-A) is a function that converts digital data (usually binary) into an analog signal (current, voltage, or electric charge). An analog-to-digital converter ( ADC ) performs the reverse function.
Computers use digital signals to communicate between the internal and peripheral devices. Some devices, like the modem and the sound card, output and receive analogue signals , but they convert these analogue signals to digital signals by using DAC (sound card) or FSK (modem).
There are different ADCs in the market such as 12-bit, 14-bit, 16-bit, 24-bit. The accuracy is directly related to the resolution of the ADC. When the resolution is higher, the accuracy becomes higher. Number of discrete analog level = 2 ^ resolution of ADC.
Computers , CDs, DVDs are some examples of Digital signal. The digital signal bandwidth is high.
ADCs follow a sequence when converting analog signals to digital . They first sample the signal, then quantify it to determine the resolution of the signal, and finally set binary values and send it to the system to read the digital signal. Two important aspects of the ADC are its sampling rate and resolution.
The first step is to take a look at the two fundamental processes involved during the analog-to-digital conversion : sampling and quantization.
Digital signals do not produce noise. Examples of analog signals are Human voice, Thermometer, Analog phones etc. Examples of digital signals are Computers, Digital Phones, Digital pens, etc.
A modem attached to a computer converts digital data to an analog signal that it uses to modulate a carrier frequency. This frequency is transmitted over a line, frequently as an audio signal over a telecommunications line, to another modem that converts it back into a copy of the original data.
The process for converting digital data into digital signal is said to be Line Coding. Digital data is found in binary format.It is represented (stored) internally as series of 1s and 0s.
Computers use analog and digital signals in order to process raw data into useful information. Whereas the former is fast at processing results, the latter gives the most accurate information. Somewhere in between is hybrid processing, which is meant to combine the advantages of the aforementioned technologies.
Analog signals are composed of continuous waves that can have any values for frequency and amplitude. Digital signals are a more reliable form of transmitting information because an error in the amplitude or frequency value would have to be very large in order to cause a jump to a different value.
Digital recordings can have a greater signal-to-noise ratio depending on the bit depth of the recording. The digital wave must walk up and down stairs, as opposed to smoothly roll over hills. The smooth analog signal matches the recorded sound wave better than the steps of a digital recording.