Benchmark ADC1 USB Instruction Manual page 7

USB acquires sync, it will perform conversion
at the sample rate of the external clock.
Off = Internal Sync
On = Locked to External Sync
Flashing = External Sync is
Selected, Not Locked
The bottom left LED in the Mode Display is
the Ext Indicator. If the Ext LED is off, then
the ADC1 USB is set to operate at a fixed
sample rate using the internal clock source.
If this LED is illuminated then the ADC1 USB
is locked to an external clock source. When
locked, the Mode Display will indicate the
sample rate.
If the reference sample rate is changed, the
ADC1 USB will automatically switch sample
rates to match the change in the reference
sample rate. If the Ext LED is flashing, the
ADC1 USB is set to sync to an external clock
source and is locking to that source. The
ADC1 USB should lock in less than 5 seconds
and if a lock doesn't occur within a 5 second
window then there's a problem with the clock
it's trying to sync to. If a sync error occurs,
verify a secure connection is present between
the ADC1 USB and the external clock source.
The ADC1 USB will lock to AES, SPDIF, WC, or
Super Clock and is very tolerant of low-level
low-quality reference signals.
External Clock Source
Synchronization
• Press up repeatedly on the Mode
Switch and cycle through the Main
Output modes until the lower left Ext
LED is either on or flashing.
Fixed Frequency Conversion
The ADC1 USB can be programmed to
convert at a fixed frequency using an internal
clock source. The following sample rate
frequencies are available: 44.1, 48, 88.2, 96,
176.4, and 192 kHz. The ADC1 USB External
Clock Input is ignored when the internal clock
source is selected.
ADC1 USB Instruction Manual
Selection of a fixed sample
frequency on the Main Outputs
• Press up repeatedly on the Mode
Switch to cycle through the available
sample frequencies until the four LEDs
in the upper left of the Mode Display
match one of the diagrams below.
Black = Lit
White = Not Lit
Gray = Irrelevant
44.1kHz
96 kHz 176.4 kHz
Sample Rate Display
Column one of the Mode Display has a "44"
LED and a "48" LED. These indicate sample
rates of 44.1 kHz and 48 kHz respectively.
Column two has an "X2" LED and an "X4"
LED. These indicate 2x or 4x multipliers.
Multiply the sample rate shown in column one
by the multiplier shown in column two. For
example, if the 44 and X2 LEDs are on, the
sample rate is 88.2 kHz (44.1 x 2 = 88.2).
Aux Output
The Aux Output can be programmed to mirror
the Main Outputs (bit for bit), or it can
48 kHz 88.2 kHz
192 kHz
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