Abbingdon Music Research DP-777 Premier Class - Manual (Page 16)

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The Zero Jitter mode utilises the original innovative GMT/IMS to totally eliminate jitter coming from the source.
AMR’s GMT clock system intelligently actualises over 28 million different real-time clock frequencies to exactly
match the dynamic input clock down to 0.001Hz (i.e. ~0.04ppm accuracy) of the source. With the new and com-
pletely jitter-free clock coupled to the Intelligent Memory System (IMS), the GMT/IMS system locks out source
jitter once and for all.
The GMT System is not a secondary PLL as used in some cases and some DACs since the late 1990’s, but an
entirely new concept. GMT instead is a system that will completely block jitter and only react to compensate any
slow drift in the clock source or to adapt to a change in the sample rate.
The GMT Zero Jitter mode is available for all digital inputs including the USB input and is the new clock standard
reference for the digital audio world.
For comparison purposes, such as to audition against another DAC, the user may press the Zero Jitter button (RD4)
to switch off the GMT/IMS. In which case, the display will show “Normal” for 1-2 seconds and the “J” will no
longer be present.
3.6 HD-Valve Digital input
The Compact Disk standard was never conceived with the notion of distinctly separate transport and DAC sections
but once this became so, SPDIF was adopted as the method to link the two together. However, SPDIF is an ana-
logue transmission system that uses what was originally a video signal format to transmit a digital system. Clearly,
this is not an elegant solution as the SPDIF clock and signal are transmitted together as if the red, blue and green
signals for a television were cobbled into a single run.
GMT/IMS system may
be switched off (for
comparison purposes)
SPDIF is an analogue
transmission system...
GMT is the world’s
first, selecting from 28
million different
frequencies