Synchrolock; Optical Out Mode - Lynx hilo User Manual

3.4.3

SynchroLock

Compare this to attenuation of 100:1 or less for professional quality analog phase-lock loops (PLL) that are used by most Pro Audio
devices. As long as the clock frequencies are within +/- 100ppm of Hilo's supported sample rates, SynchroLock will operate on the
clock signal, and insure a low-jitter clock drives the Hilo and is also sent to devices downstream (i.e. clock slaves to the Hilo).
The SynchroLock operation is a two-stage process, starting with a fast-locking analog PLL to insure that there is clock sync
immediately when a Sync Source or Sample Rate are selected, and concluding with the digitally controlled crystal-based secondary
stage. It is normal for SynchroLock to take 1-2 minutes to achieve full lock.
There are four possible states for the SynchroLock button.
Locked
Working
Range
Disabled
3.4.4

Optical Out Mode

This button shows the currently selected status of the Optical Output and allows the selection of either S/PDIF or ADAT. Pushing the
button brings up the Pop up window to change the Optical Out mode.
Lynx's SynchroLock™ technology is a very effective form of jitter reduction for digital signals.
Jitter is a type of clock error that may potentially result in distortion in an audio signal.
SynchroLock reduces jitter by a factor of 3000:1 by using the Hilo's high resolution crystal
oscillator to generate a clock signal that is phase locked to the external clock.
Either Hilo is operating off of its Internal clock, or SynchroLock has achieved full lock to
the specified external clock source. In this state, playback and recording of audio is possible.
Hilo is operating off of its Analog Phase Lock Loop to lock to the incoming clock signal,
while the SynchroLock circuitry is performing analysis on the incoming clock signal. This
may continue for 1-2 minutes. In this state, recording of audio is discouraged. Playback is
acceptable, but it should be noted that there will be an audible glitch the moment that full
lock is achieved. "Working" will occur every time a new Sync Source or Sample Rate is
selected unless SynchroLock has been disabled or the Sync Source is set to Internal.
This indicates that the selected external clock signal is operating outside of SynchroLock's
usable range. If this state is persistent, it is advisable to stop using the clock source
responsible.
The SynchroLock circuitry has been disabled by the user. In this state, the Hilo will only
clock via the Analog PLL when external Sync Sources are chosen. Pressing the
SynchroLock button will toggle between Enabled and Disabled. Generally, disabling
SynchroLock is not recommended for the best performance.
When Hilo is connected to a computer via USB, SAMPLE RATE
and SYNC SOURCE are to be controlled from software, either
globally in the OS or from within an audio application, and the
SYNCHROLOCK state also should not be altered. Therefore, these
three controls will appear "crossed out" whenever the connection to
a computer is active. To change these settings manually, one would
need to disconnect the USB cable or power down the computer.
Hilo's Optical inputs and outputs can be used for
either stereo SPDIF or 8 channels of ADAT (at 48
kHz). Hilo also supports the S/MUX protocol for
ADAT Lightpipe operation at higher sample rates.
The ADAT Ports support 4-channels at sample
rates of 88.2/96 kHz, and 2-channels at sample
rates of 176.4/192 kHz.
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Output on Right.