Mutec MC-3+ Smart Clock USB Operating Manual page 23

Operation
Different DoP Standards
There are two different DoP code conventions. DSD data in a PCM stream will be identified with so called "markers". The
first (official) convention utilizes two alternating markers with the values 0x05 and 0xFA, also called DoP markers. The second
convention uses a fixed marker with the value 0xAA, also called dCS marker. The MC-3+USB currently only supports the DoP
marker convention.
Digital Audio Format Conversion
When running the MC-3+USB in »RE-CLK« mode and applying a digital audio reference in the AES3 or S/P-DIF formats, all
digital audio outputs will transmit the source signal. Those signals at the outputs which are not of the same format as the
reference signal will be converted in real-time in compliance with the AES3 – 1992/2003 and IEC 60958 standards. As such, the
MC-3+USB acts as a digital audio format converter!
Selecting Clock Multipliers
Use the »MENU« key to navigate to the »CLOCK MULTIPLIERS« menu. Here you can select individual clock rate multiplication
factors × 1, × 2, × 4, × 8, × 256 and × 512 for each Word Clock pair and (with limited options) for the digital audio outputs by
toggling the »SELECT« key. The multipliers always refer to the base clock rate of the incoming reference signal or the selected
clock rate of the internal ultra-low jitter clock generator (»CLOCK «). Depending on the incoming or selected base clock
OUT
frequency, the MC-3+USB is capable of covering 20 audio related clock rates from 32.0 kHz to 1.536 kHz, as well as 22.5792
MHz and 24.576 MHz, and the two so-called Super clocks at 11.2896 MHz and 12.288 MHz.
Selecting the »× 256 SC«, »× 256 WC«, and »× 512« clock multipliers
The »× 256 SC« setting, the so called Super Clock, was included for clocking older digidesign ProToolsTM systems and will be
transmitted at both Word Clock output pairs with the appropriate dedicated output level. Depending on the base clock rate
(44.1 kHz or 48.0 kHz) of the received or generated reference clock signal, the outputs will transmit a clock rate of 11.2896
MHz (44.1 kHz × 256) or 12.2880 MHz (48.0 kHz × 256).
Using the »× 256 WC« setting, the system will output the same clock signals as described above, but now with the standard
Word Clock output level.
Selecting the »× 512« setting will provide the highest possible clock rates of the MC-3+USB at 22.5792 MHz and 24.576 MHz.
These were intended for clocking particular digital audio interfaces such as the hiFace EVO by M2Tech or devices by Esoteric
Audio such as the Grandioso D1, P1, P-02, K-05, K-05X, K-07, K-07X, as well as devices by TACT Audio.
Attention
Multiplying Digital Audo Signals
When a digital audio input has been selected as reference and one or both multiplication factors are set higher than × 1, the
MC-3+USB will only output black frame signals (AES3 and S/P-DIF signals without audio content) at the audio outputs. A sam-
pling rate conversion of the incoming digital audio signal will not be carried out!
Sampling Rate Limit of the Digital Audio Outputs
The multiplication of the S/P-DIF (»3«) and AES3/11(»4«) digital audio outputs is limited to a maximum sampling rate of 192.0
kHz regardless of the clock rate of the reference signal.
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