Echo Audio Mona Manuel du propriétaire télécharger pdf (Page 74)

Sample Rate

The rate at which the ADC generates the numbers is equally important in

determining the quality of a digital recording. To get a high level of

accuracy when sampling, the sample rate must be greater than twice the

frequency being sampled. The mathematical statement of this is called the

Nyquist Theorem. When dealing with full-bandwidth sound (20Hz

−

20kHz),

you should sample at greater than 40,000 times per second (twice 20kHz).

Mona allows you to sample at rates up to 96,000 times per second.

If the sampling rate is lower than the frequency you are trying to record,

entire cycles of the waveform will be missed, and the result will not

resemble the proper waveform. When the sample rate is too low, the

resulting sound has diminished high frequency content.

Figure C. Increased sample rates yield a more accurate

reproduction of the source signal.

By the way, the circuits that generate the sample rate must be exceedingly

accurate. Any difference between the sample rate used for recording and the

rate used at playback will change the pitch of the recording, just as with an

analog tape playing at the wrong speed. Also, any unsteadiness, or jitter, in

the sample clock will distort the signal as it is being converted from or to

analog form.

1 2 ... 69 70 71 72 73 74 75 76 77 78 79 ... 82 83

Pas de commentaire

Echo Audio Mona Manuel du propriétaire Page 74