Thresholds for the detection of amplitude modulation were measured in cochlear implant patients as a function of modulation frequency. Three types of threshold measures were taken: detection of amplitude modulation, detection of low-frequency sinusoidal current waveforms, and detection of beats in two-tone complexes. The temporal modulation transfer function (TMTF), defined as the plot of modul...

Initially, psychometric functions were measured for the detection of amplitude modulation (AM) or frequency modulation (FM), using a two-alternative forced-choice (2AFC) task. Carrier frequencies were 125, 1000, and 6000 Hz, and modulation rates were 2, 5, and 10 Hz. For the two lower carrier frequencies, FM detection tended to be best at the lowest modulation rate while AM detection was best a...

It has previously been reported the use of vector modulators for B1 shimming . In that application, all vector modulators were fed with the same RF pulse, and vector modulators were used to vary the overall phases and amplitudes of the RF pulses for each channel. Other groups have also reported the use of vector modulators for MRI parallel transmission . Besides the reported application in “sta...

Recent auditory physiological evidence points to a modulation frequency dimension in the auditory cortex. This dimension exists jointly with the tonotopic acoustic frequency dimension. Thus, audition can be considered as a relatively slowly-varying two-dimensional representation, the “modulation spectrum,” where the first dimension is the well-known acoustic frequency and the second dimension i...

Electronic frequency tuning of an optically pumped far infrared waveguide laser has been achieved by using the Stark effect. Frequency modulation with a 50-kHz modulation frequency and an index greater than 1 has been observed as well as a maximum modulation frequency of 300 kHz.

Birdsong assumes its complex and specific forms by the modulation of phonation in frequency and time domains. The organization of control mechanisms and intrinsic properties causing such modulation have been studied in songbirds but much less so in non-songbirds, the songs of which are often regarded as relatively simple. We examined mechanisms of frequency and amplitude modulation of phonation...

Recent auditory physiological evidence points to a modulation frequency dimension in the auditory cortex. This dimension exists jointly with the tonotopic acoustic frequency dimension. Thus, audition can be considered as a relatively slowly-varying two-dimensional representation, the “modulation spectrum,” where the first dimension is the well-known acoustic frequency and the second dimension i...

Recent auditory physiological evidence points to a modulation frequency dimension in the auditory cortex. This dimension exists jointly with the tonotopic acoustic frequency dimension. Thus, audition can be considered as a relatively slowly-varying two-dimensional representation, the " modulation spectrum, " where the first dimension is the well-known acoustic frequency and the second dimension...