Installation manual
2–26 Hardware installation
Reference Modes
The DAP must have an external reference signal to provide synchronous operation. The DAP can operate in many differ-
ent modes. Normally these modes are selected from the Jupiter file server as part of configuration. However for conve-
nience of factory test procedures, a 16 position rotary DIP switch is provided to select these modes (see page 2–21). The
very same selections are provided in the configuration software that are available using this DIP switch.
Note: It is imperative that the rotary DIP switch be placed in the “F” position so that the Digital Audio
Setup table (page 3–41) can be used to make the desired selection. If it is left in any other position, then
erratic operation will result. The DAP is shipped from the factory with the switch in the “F” position.
Two basic external reference modes are provided. They are AES/EBU reference or an NTSC or PAL video reference.
The standard and preferred method is an AES/EBU reference signal. The DAP can provide precise locking and time
alignment to an AES/EBU reference that is not possible with a video reference. To provide for maximum flexibility, the
DAP can also act as a master reference generator by locking to a video input, and providing an AES/EBU reference output
that can then be used to synchronize other AES/EBU devices.
The choices for reference modes are as follows:
1. 48 kHz narrow
2. 48 kHz NTSC video
3. 48 kHz PAL video
4. 48 kHz internal
5. 48 kHz AES auto (recommended setting)
6. 44.1 kHz narrow
7. 44.1 kHz internal
8. 44.1 kHz AES auto
9. AES automatic
10. AES vari speed
11. Manual selection (Using internal rotary DIP switch).
The following section describes each of the options in detail:
1. 48 kHz Narrow. This mode provides an ultra stable low–jitter reference at a sample rate of 48 kHz. The lock range
of the internal PLL is approximately + or – 200 ppm. When unlocked, the internal frequency defaults to 48 kHz.
This mode is normally used only for testing in the factory but could be used when an ultra stable reference is avail-
able.