I/O Converters
Updated: May 17, 2005

Harrison, creator of world class audio mixing consoles, presents the Harrison digital signal conversion system for professional audio applications. Originally developed to interface with Harrison's digital.engine™ these converters are also equally suited to operating as a stand alone audio signal converter system.

Whatever the mixing environment, be it strictly digital or a mixed signal environment, a high performance signal converter is pivotal in the success of the transition. With its compact and comprehensive approach to signal conversion, Harrison's rack mount digital converters are the ultimate solution. Modular in design, scalable for any size set up, and extraordinarily powerful, Harrison's digital converters provide a high performance comprehensive conversion solution at the most cost-effective price available. Because Harrison's digital converters employ industry standard MADI protocol, they are compatible with a wide range of devices.

Overview:
The Harrison digital signal conversion system is modular and scalable. Individual
carriers - the units which actually convert the signal - are housed in 3RU cages which can be mounted in standard racks. Any two carrier types can be combined in a single cage. Because these units are modular the system can be scaled to any size; there is no inherent limit to the number of converters that can be employed by a system. In large systems outfitted with multiple carrier types, carriers can be moved and rearranged to accommodate any set up.

Available carrier types: Analog Input (A/D), Analog Output (D/A) AES IN and AES Out

Audio Input converters translate input signals (either analog or AES) to MADI signal format for processing by an external device. The Audio Output converters translate a MADI data stream to the desired signal type (analog or AES) for output.

XLR and BNC connectors on the rear of the rack mount cages allow for interfacing a sync reference signal. Sample rate conversion is available on both AES Input carriers AND on AES output carriers.

Conversion:
Individual carriers process a single signal format i.e. the AES In carrier will convert
ONLY AES Signals to MADI. AES carriers (receive or transmit) support 28 stereo
pairs interfaced on four, 25-pin D connectors. Analog (ADC or DAC) cards support 56 balanced signals across seven, 25-pin D connectors. Each carrier supports one MADI signal stream, either going out from or into the carrier, depending on carrier type. The MADI data stream consists of 56 channels of audio transmitted over coaxial cable at up to 54 K (+12.5% of a 44.1K sample rate). The data transmission speed may also vary as low as 12.5% below the sample rate. Carriers possess power, signal presence and signal error indicators and may be reset independently.

MADI connection to and from the carrier is via 75 ohm coaxial cable with BNC-type connectors. Maximum coaxial cable length is 50 meters (164 feet). Each carrier will operate at 96K with the MADI stream reduced to 28 signals. Each rack mount cage is powered individually by either an internally mounted supply or by an optional external 2RU power supply. Redundant power supplies are available for units powered by an external power supply.

• Carriers allow 56 channels of audio conversion each (56 mono A/D or D/A or 28 stereo pairs)
• Supported vari-speed sample rates: 44.1 KHz +/- 12.5% (38.6KHz - 49.6KHz),
48 KHz +/- 12.5% (42.5KHz - 54 KHz), (96 KHz +/- 12.5% (77KHz - 108KHz), (96KHz reduces the signal number by half)
• Operating Level: +4dBu = 0VU (+24 Clip), (Other operating levels are available as an option.)
• 24-bit conversion resolution
• Total Harmonic Distortion: DAC Less than.0020%, ADC Less than.0015%
• Dynamic range greater than 110dB
• Frequency response: +.1 to -.2 dB from 20Hz - 20KHz
• Custom Harrison Phase Lock Loop (PLL) circuit for very low sample jitter
• Analog output headroom: +25dB into 600 Ohms
• TTL and AES/EBU external sync supported
• Employs latest generation multibit, delta sigma technology
• 25 pin D and 75 Ohm Coax w/ BNC Connector - customer supplied; Power cable by Harrison
• MADI via copper or optional fiber optic interface
• AES Receiver: SRC THD+N -117dBFS, Hardware by-passable SRC, Dynamic Range 128 dB, Word Width 24 bit input and output
• Dimensions: 5.25" high (3RU) x 19" wide x 24" deep
• I/O carriers may be mixed within the system
• External 2RU PSU per unit; redundant PSU option available
• Weights: Full cage: 41-46 lbs (21 kg)
• Power supply is switchable for 110V or 220V operation
• Latency: Analog In > MADI Out = .91 ms @48KHz
               MADI In > Analog Out = 1.0 ms @48KHz,
               AES In > MADI Out = 1.85 ms @48KHz,
               MADI In > AES Out = 1.85 ms @48KHz