Sony - PCM-501es DSP - digital sound processor

Input audio is digitized into a 14- or 16-bit code depending on the user’s needs. Although the 16-bit version offers better sound quality in terms of noise, dynamic range, and distortion, there is an industry standard that operates on the 14-bit system, hence the option to choose. Additionally, the error correction system is more effective in the 14-bit format, but we will discuss that later.
The conversion of an analog signal to digital involves sampling, and the 501 uses a sampling rate of 44.1 kHz, which provides a frequency response of 5 to 20,000 Hz. This, together with 16-bit sampling resolution, means that, at least in theory, one has the possibility to match the quality of CD recordings, but with an even better frequency response. As with CDs, noise and distortion are very low and speed-related effects like wow and flutter are practically imperceptible. Since sampling is linear (the input is sampled in steps with equal increments), high-frequency pre-emphasis and de-emphasis are used to further improve noise performance. This involves raising the level of high frequencies during recording and reducing them by the corresponding amount during playback, returning the sound to its original level while reducing high-frequency noise due to quantization. Quantization noise is caused by differences between the input and output waveforms, due to the digitized waveform consisting of a finite number of steps. Each point of the analog waveform is digitized to the nearest step and, although these errors are small in a 16-bit system, they are still present and appear as noise at the output. Some prerecorded materials may not have been recorded using pre-emphasis, and in this case the 501 is equipped with a system to detect this condition and automatically disable de-emphasis during playback. A status indicator shows whether the function is active or inactive.