International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The concepts of modulation index and FM improvement are simple and straightforward when the modulating signals are sinesoidal. For a complex baseband waveform such as analog TV, the FM improvement may be seriously underestimated. A method for computer simulation of video waveforms and the resulting spectra are presented.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A typical PCM/FM system is designed for a peak to peak carrier deviation of 0.7 times the bit rate of the PCM data. This value of PCM data deviation has been shown to be optimum for both PCM/FM [1] and PCM/FM+FM/FM [2] systems. However, the optimum deviation of the carrier by the FM subcarrier for a PCM/FM+FM/FM system is dependent upon the specific subcarrier type and required subcarrier signal to noise ratio at the receiver output. This paper introduces a simple method to calculate the optimum deviation of the carrier by FM subcarriers for a PCM/FM+FM/FM system. The method developed is used to calculate the optimum value of subcarrier deviation for two sample PCM/FM+FM/FM systems when IRIG constant bandwidth channels are used as FM subcarriers. The calculated optimum values of FM subcarrier deviation of the carrier, subcarrier mod index, are utilized in a companion paper to study the performance of PCM/FM+FM/FM systems [3]. The work presented herein can be extended to calculate the optimum deviation of the carrier by FM subcarriers for any PCM/FM+FM/FM system.

The dynamical underpinnings of complex computation and information transmission within the brain, while of great interest to the neuroscience community at large, remain poorly understood. One of the striking manifestations of neuronal population activity is that of rhythmic oscillations in the local field potential. It is thought that distinct patterns of these oscillations such as cross-frequency coupling within a given spatial location and coherence between disparate brain regions may represent neuronal computation and communication, respectively. Here we show such dynamics within a human temporal neocortical in vitro model. In specific, we show theta-gamma cross frequency coupling in deep and superficial layers, phase coherence between layers at theta frequencies, and a measure of communication (phase dependent power correlations) between layers at theta frequency. Additionally, we show a novel correlation between communication across layers and cross frequency coupling within layers, demonstrating a dynamic link between local computation and intralaminar communication.

The dynamical underpinnings of complex computation and information transmission within the brain, while of great interest to the neuroscience community at large, remain poorly understood. One of the striking manifestations of neuronal population activity is that of rhythmic oscillations in the local field potential. It is thought that distinct patterns of these oscillations such as cross-frequency coupling within a given spatial location and coherence between disparate brain regions may represent neuronal computation and communication, respectively. Here we show such dynamics within a human temporal neocortical in vitro model. In specific, we show theta-gamma cross frequency coupling in deep and superficial layers, phase coherence between layers at theta frequencies, and a measure of communication (phase dependent power correlations) between layers at theta frequency. Additionally, we show a novel correlation between communication across layers and cross frequency coupling within layers, demonstrating a dynamic link between local computation and intralaminar communication.