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Issue 4, August 2021 Model 5401A User Guide
Page 6 Studio Technologies, Inc.
Model 5401A
DANTE LEADER CLOCK
Why a Dedicated Dante Leader
Clock?
With Dante ubiquitous in fixed and mobile facilities of
all sizes and types, the need arose for a cost-effective,
purpose-designed, dedicated Leader clock. While an
inherent strength of Dante networking is its carefully
implemented use of the IEEE 1588 standard to ensure
that all connected devices maintain a common timing
reference, the actual performance can vary widely
depending on the specific Dante devices in use and
the overall number of devices on a network. There
are many Dante-compatible devices that can provide
adequate basic performance as a Leader clock, but
with the Model 5401A networked audio systems get
the benefits of a high-performance Primary Leader
Clock, along with additional unique capabilities. The
unit’s feature set, along with the associated internal
hardware and software, was designed to provide op-
timum performance, flexibility, and system integrity.
Timing Sources
The Model 5401A can provide excellent Leader clock
performance using its temperature- stabilized internal
oscillator, which exceeds the capability of standard
Dante devices by at least an order of magnitude.
While its standalone performance is excellent, the
Model 5401A can also be “locked” to a variety of ex-
ternal signals for integration into facilities that include
a central or main timing reference. Compatible signals
include word clock, video reference, and 10 MHz.
Word clock is a square wave signal that is often used
as a timing reference in audio-only facilities. Several
common word clock rates, including 48, 96 kHz, and
the more-exotic 192 kHz, are compatible with the
Model 5401A’s sync input. Video reference (“sync”)
signals are found in most broadcast and post-produc-
tion facilities. The Model 5401A supports the most-
common video format/rate combinations including
“black burst,” bi- and tri-level HD, and several that are
specifically intended for 4K applications. Industrial and
commercial facilities often utilize a GPS-disciplined
source of 10 MHz as a timing reference. This sine
wave signal is typically compatible with the Model
5401A’s sync input.
Word Clock Output
The Model 5401A generates a precise word clock
output signal that can be used as a timing reference
for related equipment. It’s specifically intended for
“locking” digital audio devices in applications that use
the Model 5401A to provide timing reference signals
for the associated Dante equipment. In this way, all
devices in an installation will share a common timing
reference.
The word clock output rate can be 44.1, 48, 88.2,
96, 176.4, or 192 kHz. The underlying timing source
for the word clock output is derived from the Model
5401A’s main timing source. As previously reviewed,
the internal oscillator, if desired, can be “locked” to an
external source. The main timing source is divided and
processed by the Model 5401A’s logic circuitry to cre-
ate the highly stable word clock output. This ensures
that the word clock output is synchronized with the
unit’s PTPv1 and PTPv2 server functionality.
Audio Tone Generator
The Model 5401A generates eight sine wave audio
tones intended for general-purpose use. These audio
tones are available from the Model 5401A by way
of Dante transmitter (output) channels and can be
connected, using the Dante Controller application, to
Dante receivers (inputs) on related equipment. The
flexibility of being able to interconnect signals (create
Dante “subscriptions”) between all Dante devices on
a network allows the audio tones to be used for a
variety of purposes. Configuration choices allow the
frequency and level of each sine wave tone to be
optimized for use in specific applications.
Leader Clock Support for Dante
Networks
A core part of the technology underlying Dante au-
dio-over-IP networking ensures that all connected
devices follow a common timing reference. This is
accomplished using the PTPv1 (IEEE 1588-2002)
and PTPv2 (IEEE 1588-2008) precision time proto-
cols. Any connected Dante device can be used as a
Leader clock; there is no requirement that a dedicated
Leader clock device be utilized to realize adequate
functionality. However, the actual performance can
vary widely depending on the specific Dante devices
available and the overall number of Dante devices
on a network.
Many Dante devices utilize the 2- or 4-channel
Ultimo™ ULT or UXT integrated circuits to implement
Dante connectivity. While Ultimo devices will fully