Temporal integration in amplitude modulation detection.
Temporal integration in amplitude modulation detection.
复制标题
幅度调制检测中的时间积分。
DOI：
10.1121/1.399729
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
W. Yost
中科院分区：
文献类型：
--
作者：
S. Sheft;W. Yost
用于检测宽带噪声载波的正弦幅度调制（AM）的阈值被测量为调制信号持续时间的函数。承运人是： (a) 门控持续时间超过组合刺激上升和下降时间的调制持续时间； (b) 呈现固定持续时间，其中包括调制开始前的 500 毫秒载波边缘；或 (c) 持续开启。在条件（a）中，门控载波时间调制传递函数（TMTF）表现出带通特性。对于高于个体受试者 TMTF 高通段的 AM 频率，积分函数的平均斜率为每对数单位持续时间 7.46 dB。对于边缘和连续载波条件 [(b) 和 (c)]，积分函数的平均斜率分别为每对数单位持续时间 - 9.30 和 - 9.36 dB。基于包络检波器输出积分的模拟近似于门控载波条件的结果。在边缘和连续载波条件下获得的更快的积分速率可能是由于“过度积分”，其中在短暂的调制持续时间内，部分未调制的载波包络被包含在调制信号能量的积分中。
Thresholds for detecting sinusoidal amplitude modulation (AM) of a wideband noise carrier were measured as a function of the duration of the modulating signal. The carrier was either; (a) gated with a duration that exceeded the duration of modulation by the combined stimulus rise and fall times; (b) presented with a fixed duration that included a 500-ms carrier fringe preceding the onset of modulation; or (c) on continuously. In condition (a), the gated-carrier temporal modulation transfer functions (TMTFs) exhibited a bandpass characteristic. For AM frequencies above the individual subject's TMTF high-pass segment, the mean slope of the integration functions was - 7.46 dB per log unit duration. For the fringe and continuous-carrier conditions [(b) and (c)], the mean slopes of the integration functions were, respectively, - 9.30 and - 9.36 dB per log unit duration. Simulations based on integration of the output of an envelope detector approximate the results from the gated-carrier conditions. The more rapid rates of integration obtained in the fringe and continuous-carrier conditions may be due to "overintegration" where, at brief modulation durations, portions of the unmodulated carrier envelope are included in the integration of modulating signal energy.