For receiving and storing a series of very precise measurements of the waveform, PCM is able to reconstruct mp3 download a very close approximation of the sound corresponding to said waveform. In a high quality PCM, in fact, this approach can be so close that a recorded sound is virtually indistinguishable from the source. However, for the system to function properly, must operate within certain limits. Fundamentally, there are two variables. The first is known as sampling, and is known as the second bit depth. The sample rate indicates the number of times an incoming audio signal is measured or "sample" in a given period. Usually specified in kilohertz (kHz, which means thousands of cycles per second), and audio recording called "CD quality", a sampling frequency of 44.1 kHz required.
Bit depth, on the other hand, refers to the precision with which each measurement is taken or "sample". When the AD converter to a measure of PCM digital audio input signal, and stores the measurement as a number, this number is represented as a series of 0 and 1, also known as a "binary word." Bit depth, therefore, refers to the length of the binary words used to describe each sample of the input signal received from the AD converter. Longer words allow the representation of a greater range of numbers, and thus more precise measurements and more accurate representation of a signal. In a 16 bit system, each sample is represented as a 16-digit binary word.
While this is acceptable for conventional audio CDs, other applications can be problematic. In cases where the sound mp3 download should be recorded and stored as a file on a computer, is generally considered desirable to reduce the file size as possible in order to make the most of scarce system resources. When computers are connected to the Internet, the need to minimize file sizes is becoming more urgent. Web server space is limited and can be expensive, and home phone lines simply do not have the necessary bandwidth to allow the transfer of large files to something better than the very slow speed.