Comodulation masking release (CMR): effects of signal frequency, flanking-band frequency, masker bandwidth, flanking-band level, and monotic versus dichotic presentation of the flanking band.
Comodulation masking release (CMR): effects of signal frequency, flanking-band frequency, masker bandwidth, flanking-band level, and monotic versus dichotic presentation of the flanking band.
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共调制掩蔽释放 (CMR)：信号频率、侧翼频带频率、掩蔽带宽、侧翼频带电平以及侧翼频带的单声道与双声道表现的影响。
DOI：
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发表时间：
1987
影响因子：
2.4
通讯作者：
B. Moore
中科院分区：
文献类型：
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作者：
G. P. Schooneveldt;B. Moore
在实验I中，400 ms的正弦信号的阈值进行了测量，在存在一个连续的25 Hz宽的噪声集中在信号频率（fs）范围从250到8000 Hz的1-oct步骤。掩蔽声单独或与第二个连续的25 Hz宽的噪声带（侧翼带）一起呈现，其包络与频率带相关或不相关;其中心频率范围为0.5 fs至1.5 fs。侧翼带呈现在与信号加掩蔽物相同的耳朵中（单耳条件）或在相对的耳朵中（二耳条件）。在频率带和侧翼带各自具有67 dB SPL的总体水平。共调节掩蔽释放CMR（U-C）定义为不相关和相关条件的阈值之间的差。CMR（U-C）显示了两个组成部分：一个广泛调谐的组件，发生在所有信号频率和所有侧翼频带频率，并发生在单声道和双耳分音条件;和一个组件限制在单声道条件和侧翼频带频率接近fs。这种急剧调谐的分量在低信号频率下很小，在2000和4000 Hz时显著增加，在8000 Hz时减少。实验二表明，急剧调谐组件的CMR（U-C）的幅度略有减少时，侧翼带的水平是10分贝以上的频率带，并显着减少时，该水平是10分贝以下，而宽调谐组件和两分CMR（U-C）只有轻微的影响。实验III表明，急剧调谐的组件的CMR（U-C）显着减少时，带宽的频率和侧翼频带增加到100 Hz，而宽调谐组件和两分CMR（U-C）仅略有下降。这里的论点是，一元论CMR（U-C）的急剧调谐分量是由两个掩蔽带的“载波”频率之间的拍频引起的。这在掩蔽包络中引入了周期性零点，这有助于信号检测。宽调谐分量（可能是“真正的”共模抑制）仅约为3 dB。
In experiment I, thresholds for 400-ms sinusoidal signals were measured in the presence of a continuous 25-Hz-wide noise centered at signal frequencies (fs) ranging from 250 to 8000 Hz in 1-oct steps. The masker was presented either alone or together with a second continuous 25-Hz-wide band of noise (the flanking band) whose envelope was either correlated with that of the on-frequency band or was uncorrelated; its center frequency ranged from 0.5 fs to 1.5 fs. The flanking band was presented either in the same ear (monotic condition) as the signal plus masker or in the opposite ear (dichotic condition). The on-frequency band and the flanking band each had an overall level of 67 dB SPL. The comodulation masking release, CMR (U-C), is defined as the difference between the thresholds for the uncorrelated and correlated conditions. The CMR (U-C) showed two components: a broadly tuned component, occurring at all signal frequencies and all flanking-band frequencies, and occurring for both monotic and dichotic conditions; and a component restricted to the monotic condition and to flanking-band frequencies close to fs. This sharply tuned component was small for low signal frequencies, increased markedly at 2000 and 4000 Hz, and decreased at 8000 Hz. Experiment II showed that the sharply tuned component of the CMR (U-C) was slightly reduced in magnitude when the level of the flanking band was 10 dB above that of the on-frequency band and was markedly reduced when the level was 10 dB below, whereas the broadly tuned component and the dichotic CMR (U-C) were only slightly affected. Experiment III showed that the sharply tuned component of the CMR (U-C) was markedly reduced when the bandwidths of the on-frequency and flanking bands were increased to 100 Hz, while the broadly tuned component and the dichotic CMR (U-C) decreased only slightly. The argument here is that the sharply tuned component of the monotic CMR (U-C) results from beating between the "carrier" frequencies of the two masker bands. This introduces periodic zeros in the masker envelope, which facilitate signal detection. The broadly tuned component, which is probably a "true" CMR, was only about 3 dB.