Instruction manual

ADC16 Instruction Manual – Rev A Page 9
In any external clock mode, the ADC16 will
automatically follow the sample rate of the
external reference signal. The measured
sample rate of the external source will be
displayed on the LEDs.
If the reference signal is good, the ADC16 will
lock within 8 seconds. The ADC16
UltraLockDDS™ system is very tolerant of
poor quality clock reference signals.
Clock Status Indication
Clock Error - Not Locked
'Clock Source' LED flashing rapidly
If selected clock source is present, the
corresponding clock source LED will flash
rapidly while the system is acquiring lock.
Allow up to eight seconds for the system to
lock. Failure to lock within 8 seconds is an
indication that the clock signal is corrupt or
invalid. After eight seconds, the clock system
will revert to internal sync, and the 'INT' LED
will turn on. The LED corresponding to the
selected sync source will continue to flash
once per second (indicating the "no-
reference" error condition).
Action: Check cables, connect a valid clock
signal, switch to a different clock source, or
switch the ADC16 to internal clock. Sample
rate of external clock must fall within one of
the following ranges: 28 – 50 kHz, 75-100
kHz, or 150 kHz-200 kHz
Clock Error - No Reference
'Clock Source' LED flashing once per
second, and "INT" LED ON
If no signal is present on the selected clock
input, the corresponding 'Clock Source' LED
will flash once per second, and the "INT' LED
will be on, indicating that the system has
reverted to internal sync.
Action: Check cables, connect a valid clock
signal, switch to a different clock source, or
switch the ADC16 to internal clock.
Clock Error - DAW Frequency
'Sample Rate' LEDs flashing once per
second
If the 'SAMPLE RATE' LED display is flashing,
this is an indication that the ADC16 and
optional DAW card are operating at different
frequencies. The DAW card is only functional
when the DAW sample rate matches that of
the ADC16.
Action: Change the sample rate of either the
DAW, the ADC16, or the external clock
reference. The ADC16 and DAW sample rates
must match.
Clock Error - DAW Clock Mode
'DAW' 'Clock Source' LED is flashing once
per second
If the DAW clock mode conflicts with the
ADC16 clock mode, the 'DAW' 'Clock Source'
LED will flash once per second. This can only
occur when the ADC16 is not using the DAW
as a clock source, or when the DAW card is
configured to lock to a source other than the
ADC16.
Action: Either change the ADC16 clock
source to 'DAW', or configure the DAW card
to use the ADC16 as a reference.