37. Technical Background

37.1 Lock and SyncCheck

Digital signals consist of a carrier and the data. If a digital signal is applied to an input, the re- ceiver 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 fre- quency 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 Fireface 800, 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 Fireface is set to 44.1 kHz internally (clock mode Master), and a mixing desk with ADAT output is con- nected to input ADAT1. 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 Fireface's internal sample rate. Result: When reading out the data, there will frequently be read errors that cause clicks and drop outs.

Also when using multiple inputs, a simple LOCK is not sufficient. The above described problem can be solved elegantly by setting the Fireface from Master to AutoSync (its internal clock will then be the clock delivered by the mixing desk). But in case another, un-synchronous device is connected, there will again be a slight difference in the sample rate, and therefore clicks and drop outs.

In order to display those problems optically at the device, the Fireface includes SyncCheck®. It checks all clocks used for synchronicity. If they are not synchronous to each other (i. e. abso- lutely identical), the SYNC LED of the asynchronous input flashes. In case they are completely synchronous, all LEDs are constantly lit. In example 1 it would have been obvious that the LED ADAT 1 kept on flashing after connecting the mixing desk.

In practice, SyncCheck allows for a quick overview of the correct configuration of all digital de- vices. So one of the most difficult and error-prone topics of the digital studio world finally be- comes easy to handle.

The same information is presented in the Fireface's Settings dialog. In the status display Sync- Check the state of all clocks is decoded and shown as simple text (No Lock, Lock, Sync).

User's Guide Fireface 800 © RME

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Intel Fireface 800 manual Technical Background, Lock and SyncCheck
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Fireface 800 specifications

The Intel Fireface 800 is a powerful audio interface celebrated for its high-performance capabilities and versatility in both studio and live settings. Designed to cater to the needs of musicians, producers, and sound engineers, it stands out with its rich feature set and reliable technology.

One of the defining features of the Fireface 800 is its support for an impressive 26 input and 28 output channels. This extensive I/O configuration facilitates seamless integration with a wide variety of audio production setups, allowing users to record multiple instruments simultaneously or create complex routing scenarios. The unit also boasts top-notch analog and digital converters, ensuring pristine sound quality with a dynamic range that captures the nuances of any audio source.

In terms of connectivity, the Fireface 800 is equipped with both FireWire and USB ports, making it compatible with a range of computers and devices. The device utilizes the FireWire 800 protocol, which delivers higher data transfer rates compared to its predecessor. This efficient transfer capability is crucial for maintaining audio fidelity and reducing latency, making it an ideal choice for real-time monitoring and recording.

The Fireface 800 also features standalone operation capabilities, functioning independently of a computer when needed. This is particularly useful for live performances, where reliability and reduced setup complexity are essential. Users can easily connect microphones, instruments, and other equipment directly to the Fireface 800, making it a versatile tool for a variety of scenarios.

With its low-latency driver technology, the Fireface 800 ensures smooth performance even when handling demanding audio tasks. Its advanced ADAT and S/PDIF digital inputs and outputs provide further flexibility for connecting other gear, such as additional preamps and effects processors.

Another noteworthy characteristic of the Fireface 800 is its robust build quality. Designed for regular use in professional environments, the unit features a rugged metal chassis that can withstand the rigors of transport and daily use. This ensures longevity and consistent performance for audio professionals who depend on reliable equipment day in and day out.

In summary, the Intel Fireface 800 is a versatile and powerful audio interface that caters to a wide spectrum of audio production needs. With its extensive I/O capabilities, high-quality converters, reliable connectivity options, and robust design, it continues to be a popular choice among audio professionals striving for excellence in their work.
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