Noise Analysis Method Research Articles

Elementary Methods of Reactor Noise Analysis

The analysis of reactor power fluctuations has proved useful for many reactors. Limited analysis techniques giving specific noise characteristics are proposed. Utilizing the Gaussian property of re...

Experiments with the Noise Analysis Method of Loudspeaker Measurement

The determination of the frequency response of a loudspeaker by analysis of the acoustic output resulting from a continuous-frequency spectrum electrical input has been described in the literature. It has been claimed that this method obliterates errors due to standing waves, thus permitting the true response of a loudspeaker to be measured in almost any acoustic environment. The present paper compares measurements made by the above method in a room suitable for listening tests with measurements made by the warble-tone method in the same room, and with free-space measurements using an input of slowly gliding frequency. Automatic, continuous recording was employed in all cases. In the noise analysis measurements with the usual narrow-band heterodyne analyzer the recorded irregularities due to standing waves were of the order of 15 db, and below 1000 cycles the curve bore little resemblance to the free-space response. When the analyzer band-width was increased sufficiently to smooth the standing wave peaks, irregularities actually present in the loudspeaker response also were obliterated. It is concluded that the noise analysis method possesses no peculiar advantage over other time averaging artifices in discriminating against standing wave effects.

Experiments with the Noise Analysis Method of Loudspeaker Measurement

The determination of the frequency response of a loudspeaker by analysis of the acoustic output resulting from a continuous‐frequency spectrum electrical input has been described in the literature. It has been claimed that this method obliterates errors due to standing waves, thus permitting the true response of a loudspeaker to be measured in almost any acoustic environment. The present paper compares measurements made by the above method in a room suitable for listening tests with measurements made by the warble‐tone method in the same room, and with free‐space measurements using an input of slowly gliding frequency. Automatic, continuous recording was employed in all cases. In the noise analysis measurements with the usual narrow‐band heterodyne analyzer the recorded irregularities due to standing waves were of the order of 15 db, and below 1000 cycles the curve bore little resemblance to the free‐space response. When the analyzer band‐width was increased sufficiently to smooth the standing wave peaks,...