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Hewlett Packard HP333A HP334A HP 333A/334A distortion analyzer
An audio frequency distortion analyzer basically is a precise AC volt-meter with very flat frequency response from 10Hz to 1MHz ( +/- 0.05 db). Distortion measurement takes two voltage readings where the first reading includes fundamental and harmonics, the second reading includes only the harmonics. The percentage distortion is the ratio of these two readings. (2nd reading/1st reading). If the 1st reading being set to 1 unit, the 2nd reading is the answer.
The HP334A solid stated distortion analyzers were probably the most user-friendly harmonic distortion analyzers ever made. The automatic nulling design is helpful and efficient, which speeds up the time consuming portion of distortion measurements. This model includes two control loops that automatically phase lock the bridge circuit at fundamental frequency so that only harmonics can pass the bridge.
This machine can measure audio frequency (5Hz to 600KHz) THD (Total Harmonic Distortion) down to 0.1% full scale, very useful for audio amplifiers and tube gears.
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