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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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In Reply to: Re: Jitter Schmitter posted by Bails on October 26, 2005 at 16:36:52:
Few would argue that Ed Meitner knows digital.Before designing DSD (SACD) for Sony/Phillips and before EMM Labs, Meitner designed the Museatex Bidat and complementary Melior transport with C-Lock, which lower jitter significantly, esp. for a two box system.
From the Bidat manual (link below):
"Since the ear is a velocity sensitive device, it will respond to time changes much more readily than amplitude changes."
"Frequency changes and timing are fundamental characteristics of music. These attributes are critical to the accurate reproduction of sonic information."
-E. Meitner
JITTER:
"Sounds which have been digitally recorded (i.e. quantized in time and magnitude into digital words) must be decoded at an equivalent sample rate and magnitude in order to accurately reproduce the original sounds. The stability of the sample rate clock directly affects the accuracy of conversion and it is easily shown by calculation that the required clock stability at 8Fs can be no worse than 50pS peak-to-peak in order to achieve 16-bit accuracy. This kind of deviation from perfect clock stability is called phase jitter or time jitter.
The accumulation of jitter through the playback chain is examined in a AES technical paper entitled "Time Distortions within Digital Audio due to Integrated Circuit Logic Induced Modulation (LIM) Products" in which the mechanism of jitter propagation called LIM is identified and a Museatex measurement tool for jitter analysis is introduced.
This research has led to the development of a series of proprietary Museatex circuits which prevent or reduce jitter in digital audio systems. An audio D-to-A converter must by necessity derive its timebase from the input audio data. The recovery of this clock is usually performed by one of a handful of standard IC's, all of which are sensitive to degradation of stability by every component of the preceding playback chain including the interconnecting digital cables. Yet the overall performance of the converter depends critically on the clocking of the conversion IC's with a clock having very low jitter.
C-Lock-Râ„¢ is a proprietary data receiver which uses a radically different clock recovery method. It has low sensitivity to jitter and LIM products carried in the received data stream. This provides the Bidat with low- jitter system clocks having high immunity to LIM and jitter caused by the sourcing equipment. Furthermore, this circuit ensures that any remaining jitter has a random or "white" frequency distribution allowing for clock distortion accuracy below the 20-bit level.
Museatex has made this receiver available under license to interested parties.
C-Lock-Tâ„¢ is a proprietary reclocking circuit which ensures that jitter is removed from digital outputs. This circuitry has received critical praise as used in the Museatex Melior CD-Deck, a unit which outputs a fraction of the jitter produced by competing high performance drives costing many times more.
Other C-Lockâ„¢ jitter attenuators are used to ensure that the D-to-A conversion IC's in the Bidat are driven with sufficiently stable clocks."
See also the Stereophile article on jitter:
http://www.stereophile.com/features/368/index.html
-RT
"Let me help..."
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Follow Ups
- Re: Jitter Schmitter?!!! - Rob Thomas 16:28:42 10/27/05 (0)
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