Mode Display - Benchmark ADC1 USB Instruction Manual

2) Mode Display

The Mode Display indicates the clock source,
sample rate, Aux output mode, and optical
mode (ADAT, etc).
The Mode Display indicates the operating
mode of the digital XLR, optical, and coax
outputs. It does not display the sample rate
of the USB output. The USB sample rate is
set within the software of the host computer.
Output Programming
The Main Outputs can be set to operate at a
fixed sample rate using the internal clock
source or they can be set to follow and lock to
an external clock source.
The Aux Output can be set to typical DAT or
CD-writer resolutions (TPDF-dithered; 16-bit;
44.1 or 48 kHz), or it can be set to mirror the
Main Output (bit-for-bit).
The Optical Output can be set to AES/EBU
mode or ADAT mode.
The USB Output is synchronized to the
computer host. The sample-rate is
determined by the recording software.
External Clock Source Locking
The ADC1 USB can sync to a variety of
external clock sources, including Word Clock,
Super Clock, AES, and SPDIF. Once the ADC1
USB is locked to the external clock, it will
synchronize the Main Outputs (and Aux if
selected) to the sample rate of the Ext Ref
Input (external reference 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.
ADC1 USB Instruction Manual – Rev C
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.
If a lock doesn't occur within a 5 second
window, there may be a problem with the
external reference clock. If a sync error
occurs, verify a secure connection is present
between the ADC1 USB and the external clock
source. The ADC1 USB 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 Sample-Rate Conversion
The ADC1 USB can be programmed to
convert at a fixed sample rate using an
internal clock source. The following sample
rate frequencies are available: 44.1, 48, 88.2,
96, 176.4, and 192 kHz. The Ext Ref Input is
ignored when the internal clock source is
selected.
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