More and more users have begun to use digital signal telephone, but in some underdeveloped areas analog signal telephone is still commonly used. Many users confuse analog signals with digital signals. So what is an analog phone? What is a digital signal telephone?
Analog telephone - A telephone that transmits sound through analog signals. Electrical analog signal is mainly refers to the amplitude and corresponding continuous electrical signal, this signal can be analog circuit for various operations, increase, add, multiply and so on. Analog signals exist everywhere in nature, such as daily temperature changes.
A digital signal is a digital representation of a time signal (represented by the sequence of 1 and 0), usually obtained from an analog signal.
Advantages and disadvantages of digital signals:
1, occupy a wide frequency band. Because the line transmits a pulse signal, the transmission of digital voice information needs to account for 20K-64kHz bandwidth, and an analog voice path only occupies 4kHz bandwidth, that is, a PCM signal accounts for several analog voice paths. For a certain channel, its utilization rate is reduced, or its requirements for the line are increased.
2, the technical requirements are complex, especially the synchronization technology requires high precision. To correctly understand the meaning of the sender, the receiver must correctly distinguish each code element, and find the beginning of each information group, which requires the sender and receiver to strictly realize synchronization, if the formation of a digital network, the synchronization problem will be more difficult to solve.
3, the analog/digital conversion will bring quantization error. With the use of large-scale integrated circuits and the popularity of broadband transmission media such as optical fiber, more and more digital signals are used for information storage and transmission, so analog signals must be converted to analog/digital, and quantization errors will inevitably occur in the conversion.
Post time: Feb-05-2024
