Sample Rate Conversion (SRC)

In general you need to make sure that any digital inputs are synchronized to the system sampling rate.

If for any reason you cannot synchronize the AES/EBU 1-4 (1-8 on H8000) or S/P DIF 1/2 digital inputs to the system sampling rate, use sample rate conversion (SRC). The sample rate

conversion pages are the "bottom" menu pages under clock in the SETUP area. By turning SRC Mode on for the appropriate digital input, the H8000FW will adjust the input sampling rate to match the system sampling rate. The sample rate before conversion is displayed in the Input SR x/x field. In this example, our internal clock rate is 48kHz. The SRCs are converting these 44.1kHz inputs to 48kHz.

The sample rate conversion algorithm is of a high quality and its presence is normally undetectable without the use of expensive test equipment. Nevertheless, the true audiophile will try to synchronize the input devices to the H8000FW without using sample rate conversion in order to achieve the best possible results.

Note that sample rate conversion is only available on the above inputs – other digital inputs need to be locked if they are used.

Word Clock Termination

Any cable has a characteristic impedance that should be matched to both the signal source and destination impedance for best results with high speed sharp edged signals such as Word Clock. This becomes more important with longer cables.

Most Word Clock signals are generated with 50 Ohm source impedance, whereas the BNC cables used to connect to them may have 50 or 75 Ohm impedances – clearly the former are to be preferred.

So, we have covered the source and the cable – what about the destination ? If we only have a single destination it is easy – the destination must also be 50 Ohm – this is ensured by the use of termination. An input will be either terminated meaning its impedance is set to 50 Ohm, or un-terminated meaning it has a high impedance that will not load the cable.

With multiple destinations only the one at the end of the cable needs to be terminated – intermediate destinations need not and should not be terminated, as long as the “stub length” of the cable to them is short. These should be connected by the use of a BNC

“T” connector or splitter attached directly to their inputs so as to 88