gh@geovision.uucp (George Hagilaris) (05/17/90)
In article <4848@daffy.cs.wisc.edu> pochron@cat25.cs.wisc.edu (David Pochron) writes: [stuff deleted] >Sound frequency is measured in hertz or Khz, but the rate at >which the chips can output data to the DAC is in SPS. The Amiga can do 28K SPS >which means the highest frequency it can play is 14 Khz. >CD players are at 41.???K SPS and they have a freq. response of about 20 Khz. > (just right for human ears) 28K SPS does not mean that the _highest_ frequency the Amiga can play is 14KHz. A sampling rate of 28KHz (ie. 2*14KHz), or 28K SPS (same thing), is the sampling rate required to accurately reproduce a 14KHz tone (this includes harmonics as well). You can still _play_ a sound which is greater than 14KHz, but if you are only using a 28KHz sampling rate (28K SPS), then you will not get a "faithful" reproduction of that sound. The rule is that you sample at (at least) twice the frequency of the _highest_ frequency harmonic of the sound you are sampling. A sampling frequency of 40KHz is enough because (hardly any) people can hear sounds/harmonics/tones above 20KHz. -- George Hagilaris uunet!geovision!rock!gh