Analog data transmission

The principle of analogue transmission

THE analog data transmission is to circulate information on a physical transmission medium in the form of a wave. The data transmission is done through a simple carrier wave whose sole purpose is to transport the data by modifying one of its characteristics (amplitude, frequency or phase).

For this reason, analogue transmission is generally called transmission by carrier wave modulation. According to the parameter of the carrier wave that will vary, three types of analog transmission are distinguished: by amplitude modulation, by frequency modulation and by phase modulation.

How analog transmission of analog data works

This type of transmission designates a scheme in which the data to be transmitted are made directly in analog form. So, to transmit this signal, the ETCD (Data Circuit Terminal Equipment) must perform a continuous convolution of the signal to be transmitted and the carrier wave, that is, the wave that will transmit will be an association of the carrier wave with the signal that must transmit. In the case of a transmission by amplitude modulation, for example, the transmission is done as follows:

Analog transmission of digital data and the Modem

When digital data appeared, the transmission systems were still analog. So it was necessary to find a way to transmit digital data in an analog way. The solution to this problem was the creation of the modem. Its role in emission is to convert digital data (a set of 0 and 1) into analog signals (the continuous variation of a physical phenomenon). On the other hand, its role in reception is to convert the analog signal into digital data.

Photo: © Markus Spiske – Unsplash.