Computers are digital devices, meaning they perform all calculations using ones and zeros. This method of computing is referred to as the “binary system,” and is the heart of all digital technology. Devices such as hard drives, CD recorders, and Mini DV camcorders are digital devices, and therefore record data digitally, as ones and zeros.
VCRs, tape players, and record players, on the other hand, are analog devices. This is because they record data linearly from one point to another. Imagine a bumpy line moving from left to right — that is what an analog audio recording would look like. Analog devices read the media, such as tapes or records, by scanning the physical data off the media.
For example, a record player reads the bumps and dips in the grooves of the record and translates the information into an audio signal. An audio CD player, however, reads ones and zeros off a compact disc and translates that information into an audio signal. However, the ones and zeros only estimate the actual soundwave, whereas a record player records the exact sound. When you hear terms like “sampling rate” or “bit rate,” these refer to how many times per second the digital signal is sampled. The higher the number, the more accurate the estimate is, which translates into higher quality sound or video.
So why is digital technology used if analog provides a better representation of the recorded information? Well, since computers perform digital computations, they can only work with digital media. Therefore, all analog audio or video media must be converted to digital to work on a computer. Once the information is digital, computers can be used to edit the data and create effects that were never possible with analog media. Digital media is non-linear, which means it can be edited or played back starting at any point, which can be a huge timesaver compared to working with tape. Digital information also does not “wear out” after repeated use like tapes or records do, which results in much better longevity for digital media.
To summarize, a digital signal is an estimation of analog data. Digital recordings are made with ones and zeros, while analog recordings are made with linear bumps and dips. While digital information is not as exact as analog information, it can be used with other digital devices, such as computers, making editing and reproduction of the information easier and faster. Because digital media is more compatible and does not degrade over time, it has become the common choice for today’s audio and video formats.