Fantini D A
Department of Psychology, University of Minnesota, Minneapolis 55455.
J Acoust Soc Am. 1989 Apr;85(4):1691-8. doi: 10.1121/1.397958.
The effects of the presence of an amplitude discontinuity in the spectrum of a noise masker on frequency discrimination performance were examined. First, detection thresholds as a function of masker level were obtained for pure-tone signals masked by either simultaneous or forward white and low-pass maskers. Then frequency discrimination thresholds were obtained using four masker levels that were chosen to yield predetermined masked thresholds, with signal levels corresponding to each of three sensation levels above these masked thresholds. The principal results indicate that frequency discrimination is poorer in simultaneous low-pass noise than in simultaneous white noise, and that this difference in performance increases with increasing sensation level and with increasing masker level. These results are inconsistent with an explanation based on the pitches generated at spectral edges ("edge pitch"), pitch shifts, or disruption of phase-locking information, but are generally consistent with an explanation based on lateral suppression. It is proposed that a release from suppression may occur in filtered noise backgrounds at high noise levels and at high sensation levels. The reduced suppression may result in poorer frequency discrimination due, in part, to reduced signal detectability.
研究了噪声掩蔽器频谱中幅度不连续的存在对频率辨别性能的影响。首先，针对由同时性或前向白噪声和低通噪声掩蔽的纯音信号，获取了作为掩蔽器电平函数的检测阈值。然后，使用四个掩蔽器电平获得频率辨别阈值，选择这四个掩蔽器电平以产生预定的掩蔽阈值，信号电平对应于高于这些掩蔽阈值的三种感觉电平中的每一种。主要结果表明，同时性低通噪声中的频率辨别比同时性白噪声中的频率辨别更差，并且这种性能差异随着感觉电平的增加和掩蔽器电平的增加而增大。这些结果与基于频谱边缘产生的音调（“边缘音调”）、音调偏移或锁相信息中断的解释不一致，但总体上与基于侧向抑制的解释一致。有人提出，在高噪声水平和高感觉水平的滤波噪声背景中可能会发生抑制解除。抑制的降低可能部分由于信号可检测性降低而导致频率辨别变差。
