User Manual

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User's Guide Babyface Pro FS © RME
27.6 General
x Power supply: USB bus power or external power supply
x Idle power consumption: 2.8 Watts
x Typical power consumption: 3.7 Watts
x Max. power consumption: 5.4 Watts
x Current at 5 V bus power operation: 700 mA (3.7 Watts)
x Current at 12 V external power: 313 mA (3.7 Watts)
x Dimensions (WxHxD): 108 x 35 x 181 mm (4.25" x 1.4" x 7.1")
x Weight: 680 g ( 1.5 lbs)
x Temperature range: +5° up to +50° Celsius (41° F up to 122°F)
x Relative humidity: < 75%, non condensing
Typical power consumption: Playback 1 kHz sine 0 dBFS, 2 x 32 Ohm at TRS 3.5 mm, XLR
loopback -> nearly all LEDs lit in medium brightness.
Maximum power consumption: same, but XLR inputs shorted and phantom power activated.
28. Technical Background
28.1 Lock and SyncCheck
Digital signals consist of a carrier and the data. If a digital signal is applied to an input, the
receiver has to synchronize to the carrier clock in order to read the data correctly. To achieve
this, the receiver uses a PLL (Phase Locked Loop). As soon as the receiver meets the exact
frequency of the incoming signal, it is locked. This Lock state remains even with small changes
of the frequency, because the PLL tracks the receiver's frequency.
If an ADAT or SPDIF signal is applied to the Babyface Pro, the corresponding input LED starts
flashing. The unit indicates LOCK, i. e. a valid input signal (in case the signal is also in sync, the
LED is constantly lit, see below).
Unfortunately, LOCK does not necessarily mean that the received signal is correct with respect
to the clock which processes the read out of the embedded data. Example [1]: The Babyface
Pro is set to 44.1 kHz internally (clock mode Master), and a mixing desk with ADAT output is
connected to input ADAT. The corresponding LED will show LOCK immediately, but usually the
mixing desk's sample rate is generated internally (also Master), and thus slightly higher or lower
than the Babyface Pro's internal sample rate. Result: When reading out the data, there will
frequently be read errors that cause clicks and drop outs.
In order to display those problems optically at the device, the Babyface Pro includes
SyncCheck. It checks all clocks used for synchronicity. If they are not synchronous to each
other (i.e. absolutely identical) the SYNC LED flashes. In case they are completely synchronous
the LED is constantly lit. In the above example the user would have noticed quickly that the LED
kept on flashing after connecting the mixing desk.
The same information is presented in the Babyface Pro's Settings dialog. In the status display
Input State the state of the input clock is decoded and shown as simple text (No Lock, Lock,
Sync).
In practice, SyncCheck allows for a quick overview of the correct configuration of all digital
devices. So one of the most difficult and error-prone topics of the digital studio world finally
becomes easy to handle.