• ULDO-"Nacho" Ultra Low Distortion Oscillator and Notch Filter, Bare PC Board

This is the ultra low distortion oscillator PC board described in the Pro Audio design Forum. "ULDO," the ultra low distortion oscillator portion of the board, generates 1 kHz tone with THD levels typically -140 dB below the "carrier' (oscillator output) level. -140 dBc, which is dB below carrier, is a THD level of 0.00001% or 0.1 parts per million.

ULDO's output is balanced with a 49.9Ω per leg output impedance. The maximum balanced output level (unloaded) is approximately +26 dBu with ±15V supplies.

The output level is DC-controlled by an external potentiometer over an approximate 26 dB range. An optional attenuator, "ATTO," is available to provide output attenuation to -70 dBu.

"Nacho," the notch filter portion of the PC board, extends measurement dynamic range.  Filtering the 1 kHz fundamental and adding 40 dB gain allows conventional audio-grade A/D converters and FFT software to measure distortion below the unassisted noise floor of the converter. A spreadsheet, available for download assists converting FFT levels to total THD.

Construction and assembly information for ULDO-Nacho can be found here: Ultra Low Distortion Oscillator and Notch Filter Assembly Instructions And Test

A Mouser Project Manager parts list is also available.

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ULDO-"Nacho" Ultra Low Distortion Oscillator and Notch Filter, Bare PC Board

  • $69.95


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ULDO-"Nacho" Ultra Low Distortion Oscillator and Notch Filter, Assembled and Tested

ULDO-"Nacho" Ultra Low Distortion Oscillator and Notch Filter, Assembled and Tested

This is an assembled and tested ultra low distortion oscillator PC board described in the Pro Audio ..

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