The process of converting a digital signal (in the form of zeros and ones or highs and lows) to an analog signal is known as digital-to-Analog Conversion (D/A) (one with infinitely many levels and states). A digital to analog converter, or DAC, is an electrical device used for this purpose. A digital signal is converted to an analog signal by a digital-to-analog converter (DAC).

It is necessary to convert digital data into an analog signal before sending it over an analog medium. In terms of data formatting, there are two possibilities. Filters that are used to filter and pass frequencies of interest are known as

Bandpass filters: A bandpass filter allows a range of frequencies to pass through it.

Low-pass filter: A low-pass filter passes low-frequency signals.

Digital-to-analog conversion is the process of converting digital data into a bandpass analog signal. Analog-to-analog conversion is the process of converting a low-pass analog signal into a bandpass analog signal.

Digital-to-Analog Conversion

Data from one computer is transformed into analog signals before being transmitted to another through an analog carrier. To reflect digital data, analog signals are transformed. The amplitude, frequency, and phase of an analog signal define it.

Digital-to-analog conversions can be divided into four categories:

• Amplitude Shift Keying

  The amplitude of the analog carrier signal is changed to reflect binary data in this conversion technique. The amplitude is kept when binary data indicates digit 1; otherwise, it is set to 0. The frequency and phase of the original carrier signal remain unchanged.

• Frequency Shift Keying

  The frequency of the analog carrier signal is changed to reflect binary data in this conversion technique. The f1 and f2 frequencies are used in this technique. One is used to represent binary digit 1 while the other is used to represent binary digit 0. The carrier wave’s amplitude and phase are kept.

• Phase Shift Keying

  The phase of the signal is changed when a new binary symbol is encountered. The original carrier signal’s amplitude and frequency are kept.

• Quadrature Phase Shift Keying

  The phase of QPSK is changed to reflect two binary digits at the same time. This is accomplished in two stages. The primary binary data stream is split into two equal sub-streams. In both sub-streams, serial data is changed to parallel, and then each stream is converted to a digital signal using the NRZ approach. After that, the two digital signals are merged.