Forward masking of frequency modulation.
Forward masking of frequency modulation.
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DOI：
10.1121/1.4754531
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
Andrew J. Byrne;M. Wojtczak;N. Viemeister
中科院分区：
文献类型：
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作者：
Andrew J. Byrne;M. Wojtczak;N. Viemeister
正弦频率调制（FM）的前向掩蔽测量有三种类型的掩蔽：FM，幅度调制（AM），并通过结合FM音调的幅度谱与随机分量相位创建掩蔽。对于所使用的信号FM速率（5、20和40 Hz），FM掩蔽器相对于没有掩蔽器将频率偏差方面的检测阈值提高了约5倍。AM掩蔽器产生的效果要小得多，这表明FM到AM转换对FM前向掩蔽没有实质性贡献。FM掩蔽器的调制深度具有非单调效应，在可能的深度范围内的中间值处观察到最大掩蔽，而随机相位FM掩蔽器产生较少的掩蔽，反对FM前向掩蔽的基于频谱的解释。宽FM率选择性的前向掩蔽观察到4 kHz和500 Hz载波。作为掩蔽信号延迟的函数测量的持续时间显示出从FM前向掩蔽的缓慢恢复，对于高达500 ms的延迟具有残余掩蔽。FM前向掩蔽效应类似于针对AM观察到的效应[Wojtczak和Viemeister（2005）. J. Acoust.美国社会188，3198-3210]，并且可以反映对FM的调制速率选择性神经适应。
Forward masking of sinusoidal frequency modulation (FM) was measured with three types of maskers: FM, amplitude modulation (AM), and a masker created by combining the magnitude spectrum of an FM tone with random component phases. For the signal FM rates used (5, 20, and 40 Hz), an FM masker raised detection thresholds in terms of frequency deviation by a factor of about 5 relative to without a masker. The AM masker produced a much smaller effect, suggesting that FM-to-AM conversion did not contribute substantially to the FM forward masking. The modulation depth of an FM masker had a nonmonotonic effect, with maximal masking observed at an intermediate value within the range of possible depths, while the random-phase FM masker produced less masking, arguing against a spectrally-based explanation for FM forward masking. Broad FM-rate selectivity for forward masking was observed for both 4-kHz and 500-Hz carriers. Thresholds measured as a function of the masker-signal delay showed slow recovery from FM forward masking, with residual masking for delays up to 500 ms. The FM forward-masking effect resembles that observed for AM [Wojtczak and Viemeister (2005). J. Acoust. Soc. Am. 188, 3198-3210] and may reflect modulation-rate selective neural adaptation to FM.