15.09.2005, 02:13 PM
im: standard (din+smpte): 60hz -3db + 7khz -12db;
auch: 11k+12khz, oder 19k+20k gleicher pegel, im erscheint bei 1khz;
SMPTE/DIN IMD The most common IMD measurement. SMPTE standard RP120-1994 and DIN standard 45403 are similar. Both specify a two-sine wave test signal consisting of a large amplitude low-frequency tone linearly mixed with a high-frequency tone at ¼ the amplitude of the low frequency tone. SMPTE specifies 60 Hz and 7 kHz mixed 4:1. The DIN specification allows several choices in both frequencies, with 250 Hz and 8 kHz being the most common.
ITU-R (old CCIF), Twin-Tone, or Difference-Tone IMD All these terms refer to the same test and are used interchangeably. The test specifies two equal-amplitude closely spaced high frequency signals. Common test tones are 19 kHz and 20 kHz for full audio bandwidth units. While all combinations of IM distortion products are possible, this test usually measures only the low-frequency second-order product falling at f2-f1, i.e., at 1 kHz.
ich mache zt: 3k+5khz, gl. peg., im bei 2khz; hat den vorteil, dass auch gleich der in-audio klirr zu sehen ist und komplexere im zb 2xf1 -f2, also 1k oder 6k usw. alle einfach zu messen sind.
++ zur 384 khz (phillips) frage: ergibt sich einfach aus 48khz 8x oversampling, standard bei vielen 1-bit dacs.
auch: 11k+12khz, oder 19k+20k gleicher pegel, im erscheint bei 1khz;
SMPTE/DIN IMD The most common IMD measurement. SMPTE standard RP120-1994 and DIN standard 45403 are similar. Both specify a two-sine wave test signal consisting of a large amplitude low-frequency tone linearly mixed with a high-frequency tone at ¼ the amplitude of the low frequency tone. SMPTE specifies 60 Hz and 7 kHz mixed 4:1. The DIN specification allows several choices in both frequencies, with 250 Hz and 8 kHz being the most common.
ITU-R (old CCIF), Twin-Tone, or Difference-Tone IMD All these terms refer to the same test and are used interchangeably. The test specifies two equal-amplitude closely spaced high frequency signals. Common test tones are 19 kHz and 20 kHz for full audio bandwidth units. While all combinations of IM distortion products are possible, this test usually measures only the low-frequency second-order product falling at f2-f1, i.e., at 1 kHz.
ich mache zt: 3k+5khz, gl. peg., im bei 2khz; hat den vorteil, dass auch gleich der in-audio klirr zu sehen ist und komplexere im zb 2xf1 -f2, also 1k oder 6k usw. alle einfach zu messen sind.
++ zur 384 khz (phillips) frage: ergibt sich einfach aus 48khz 8x oversampling, standard bei vielen 1-bit dacs.
Don't worry about getting older. You're still gonna do dump stuff...only slower