Yamaha DSP5D Owner's Manual - Page 38

4 Connections and setup Word clock connections and settings This section explains the word clock settings required in order to send or receive digital audio between the PM5D/DSP5D and an external digital device. About word clock When digital audio signals are being sent or received between multiple devices, the devices must process the audio signals at the matching timing. For example if the audio signal processing is not synchronized, the signals will not be transmitted correctly and unpleasant noise will occur even if both devices are set to the same sampling frequency. The signal used to synchronize digital audio signal processing is called "word clock." Normally, one device transmits a reference word clock signal, and the other devices receive this word clock signal and synchronize to it. (The transmitting device is called the "word clock master" and the receiving devices are called "word clock slaves.") The word clock can be synchronized between the PM5D/ DSP5D and external devices in either of two ways; you can send/receive a word clock signal by itself, or use the clock data that is included in a digital audio signal. The WORD CLOCK IN/OUT connectors on the rear panel of the PM5D (front panel for the DSP5D) are used to send/receive a word clock signal by itself. In general, word clock connections can be made in either of the following two ways. Using daisy-chain connections In this method, the signal is distributed sequentially; the WORD CLOCK OUT connector of the first device is connected to the WORD CLOCK IN connector of the second device, and so on. Turn all of the PM5D's 75Ω ON/OFF switches ON. On the DSP5D, this is fixed at 75Ω ON. This method is not recommended for large systems. If an external device does not have WORD CLOCK IN/ OUT connectors, the clock data included in the digital audio signal is used. In this case, both the digital audio signal and the clock data are sent from the DIGITAL OUT jack of the word clock master to the DIGITAL IN jack of the word clock slave. Digital audio signal + Clock data DIGITAL OUT Device A Word clock master DIGITAL IN Device B Word clock slave Selecting the word clock master When digitally connecting the PM5D/DSP5D to an external device, you must select the source that will be the word clock master for the system. 1 Repeatedly press the [SYS/W.CLOCK] key of the DISPLAY ACCESS section until the WORD CLOCK screen appears. WORD CLOCK MASTER CLOCK SELECT area Word clock master 75Ω ON/OFF= ON WC OUT (BNC) WC IN (BNC) WC OUT (BNC) Device A Word clock slave 75Ω ON/OFF= ON WC IN (BNC) WC OUT (BNC) Device B Word clock slave 75Ω ON/OFF= ON WC IN (BNC) Device C Word clock slave 75Ω ON/OFF= ON Using a word clock distribution box In this method, a special word clock distribution box is used to distribute the signal from the word clock master to multiple word clock slaves. Turn ON all of the 75Ω ON/ OFF switches. Word clock master WC OUT 75Ω ON/OFF= ON (BNC) Word clock distribution box In this screen you can select the master clock, and check the input signal synchronization status for each slot or jack. Note When you switch the word clock source, noise may occur due to loss of synchronization. You must lower the level of your monitoring equipment before you perform the following operation. Use the MASTER CLOCK SELECT area located in the upper part of the screen to select the master clock source. You can choose one of the following sources. WC IN (BNC) Device A Word clock slave 75Ω ON/OFF= ON WC IN (BNC) Device B Word clock slave 75Ω ON/OFF= ON WC IN (BNC) Device C Word clock slave 75Ω ON/OFF= ON WC IN (BNC) Device D Word clock slave 75Ω ON/OFF= ON 38 PM5D/PM5D-RH V2 / DSP5D Owner's Manual Operating section