Lexicon 20/20 AD manual 00k 10.0k 12.0k 14.0k 16.0k 18.0k

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20/20 AD User Guide

Using the 20/20 AD

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Plot of noise + distortion vs. frequency for the 20/20 AD in 2- channel mode with a -60dBfs sinewave at 1kHz.

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WIDE dither is added before truncation. Noise floor is ele- vated further, but harmonic distortion is removed.

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PONS dither. Noise floor is down almost to the untruncated level in the critical band (2-4kHz), but significantly increased at high frequencies.

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20/20 AD in 2-channel mode, truncated to 16 bits without dither. Note harmonic distortion (spikes at multiples of 1kHz) and elevated noise floor.

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HF dither is added before truncation. Noise floor in audio range is lowered by 3dB — at the expense of increased noise above 20kHz.

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20BIT dither is added before truncation. This is similar to HF dither, but at a lower level. The dither reduces spurious tones (low-level spikes visible in the first plot) at the expense of a slightly elevated noise floor.

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Contents 20/20 AD Precautions Electrostatic Discharge ESD Precautions Contents AES/EBU Interface Professional IntroductionPower Mounting Controls and ConnectorsConverter 20/20 AD Front Panel ControlsCompressor Level MetersDisplay LinkSynchronization Output Formatting Alternate ModesPress and hold Then press one of these BAL/UNBAL 20/20 AD Rear Panel ConnectorsConnectors Audio ConnectionsXLR Pinout Cables Signal Type Attenuator DBu DBV Signal Type Pin Pin3Termination and Grounding via Internal Jumpers Word Clock These instructions are for use by qualified personnel onlyAnalog Jumpers Balanced Unbalanced Input Signals Front panel Adjustments DB ScaleMeter Ballistics AES Sync Word Clock Synchronization and Sample RateInternal and External modes StatesPsychoacoustically Optimized Noise Shaping Pons About Dither00k 10.0k 12.0k 14.0k 16.0k 18.0k Dynamic Range Compression Automatic Offset Removal Compressor ModesInput Gain Threshold Release Compressor Knob ValuesTransfer Functions Non-linearUsing the 20/20 AD Lexicon Link Realigning Two DAT Recordings Digital Sinewave GeneratorGain Definition of Terms Definition of Terms Oak Park Bedford, MA 01730 USA Tel Fax