Why does the voice on the phone sound different from the real thing? (Principles of wireless communication and voice modulation)

The reason why the voice you hear over the phone sounds different from the real thing is that data loss occurs due to sampling during the conversion and transmission of voice into electrical signals. The fields of electrical engineering and information and communication are researching ways to minimize this loss and make communication more efficient.

 

Anyone who has seen the movie “The Voice of the Gnome” will remember the eerie voice of the killer in the movie. In the movie, the parents of the kidnapped child desperately try to find the killer, but they are unable to catch the killer because the only clue to the killer is the voice over the phone. Why is the voice over the phone not enough to catch the killer? This is because the voice on the phone is not the same as the actual person’s voice. To understand why this is the case, we need to understand how voices are transmitted through phones.
First, let’s take a look at how phones work. There are three main parts to a phone’s operation. First, there’s the process of converting our voice into electrical signals. When we produce our voice through the vibration of our vocal cords, it causes the air to vibrate, and that vibration is transmitted to the phone. This causes the diaphragm in the phone to vibrate, which changes its resistance and produces a current proportional to that change. This is called the voice current. The second is the process of transmitting the voice information converted into electrical signals to the other phone. This is where electrical engineering, especially telecommunications, comes into play. This is the transmission of data to the other person’s phone, either wired or wireless. Third, the electrical signal is converted back into voice information. This process is easy to understand if you think of it as the opposite of the first one. The transmitted voice current causes the diaphragm to vibrate, which in turn causes the air to vibrate, and the resulting sound is what we hear.
But where in this process does the modulation of the voice occur? It’s the second part of the process. The amount of speech information that is converted into electrical signals is very large, so in order to convey this information efficiently, a technique called sampling is used. Sampling is a method of extracting a small sample of a large amount of data at regular intervals and transmitting only that sample. This greatly reduces the amount of data that needs to be sent and makes communication more efficient. The recipient of the data then uses the samples to restore the original data. However, there is a problem with this process, and that is the loss of data, or in this case, the change in voice. Since the purpose of communication is to transmit information, a minimum sample is extracted and transmitted so that the content does not change, but the voice is not perfectly transmitted.
Electrical engineering, especially in the fields of radio waves and telecommunications, is studying various areas, including how to minimize the loss of information during this sampling process. They are also actively researching ways to send and receive the same amount of data faster and more accurately. The result of this research is the cell phones we use today. Wireless communication is much more advanced than what we used to do with landline phones, and a variety of communications such as text messaging and video calls have been developed and commercialized. In addition, Internet communication such as 3G and 4G is also a field that is being emphasized these days, so there are endless possibilities for the development of communication technology in the future.