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Apogee DA-16 User's Guide

played simultaneously through the DA-16, you would probably want to synchronize the DA-88 using word clock

from a BRC so that you don't end up with two asynchronous sources.

The second function of this button is to select the channel(s) to calibrate in Calibration Mode (page 15).

SAMPLE RATE

To the right of the SYNC button is the SAMPLE RATE indicator. The yellow LEDs indicate the incoming sample

rate from the source selected using the SYNC and CH 1-8/9-16 buttons. The incoming sample rate is automat-

ically detected, and thus does not need to be user-selectable on the DA-16.

While the DA16 is in S/MUX mode, the correct sample rates of 88.2 kHz and 96 kHz will be displayed. The DA-

16's clock is designed to lock to incoming sample rates in the range of 44.1 kHz to 96 kHz, ±10%. This accom-

modates all pull-up and pull-down sample rates within this range as well as pitch-shifted and other irregular

rates.

Below the sample rate indicators is the green WIDE lock indicator.

When lit, this LED shows that the unit has achieved WIDE lock (up to ±

150 degrees phase error). With all but the most extremely jittery input

signals, this LED should light quickly when the DA-16 is fed an input sig-

nal. The red NARROW LED illuminates when the unit has achieved a

tighter lock (less than ±5 degrees phase error). Again, this LED should

illuminate fairly quickly after WIDE lock is achieved. The DA-16's normal

functional state is with both NARROW and WIDE LEDs illuminated. If

the NARROW LED fails to light, check the quality of your incoming sig-

nal and make sure that the DA-16's SYNC and CH source selections are

set correctly.

The DA-16 will lock to signals with large amounts of jitter and/or phase errors. However, it is always worth try-

ing to locate the source of errors of this type.

When selecting 'AES' as a digital source and the sync source, individual channel pairs (1/2, 3/4, 5/6, etc.) can be

selected as the sync source using the DIP switches on the rear-panel. Thus, for example, if you have several DAT

players connected to the AES D-sub connector on the rear panel, you can select one of them as the DA-16's

sync source.

NOTE: While the DA-16 has Word Clock selected as its sync source, AND the S/MUX dip switch is in the ON

position, AND one of the banks is selected as Optical, then the DA-16 will enter S/MUX mode and corre-

spondingly indicate 88.2 or 96 kHz sample rates. If you do not wish to engage S/MUX mode in this situation,

simply turn the S/MUX mode DIP switch to the OFF position, or select an input source other than Optical on

the unused bank.

CH 1-8 and CH 9-16

These buttons select the appropriate input for each set of 8 channels – AES, TDIF, or ADAT (Normal or SMUX

mode). The CH 1-8 and CH 9-16 buttons select the incoming digital source for the respective channel bank. The

DOWN and UP markings above these buttons come into play in the level calibration mode and work in con-

junction with the 'CH SET' marking above the SYNC button.

Indicators

There is an LED indicator for each button selection as well as for each audio channel. Each sample frequency

has its own LED, in addition to WIDE LOCK and NARROW LOCK. When a sync source is selected, wide lock will

establish first when the PLL has locked to within approximately ±150 degrees. The 2-stage re-clocking buffer

will insure that no audio data is lost while wide lock is fully indicated. After wide lock is established, the PLL will

adjust its phase relationship to the sync source until narrow lock is established. If narrow lock cannot be estab-

lished (ie if the NARROW LOCK light does not illuminate steadily after a reasonable time), check the quality (jit-

ter) of the incoming sync source.

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