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This paper deals with the design and performance analysis of a ring oscillator using CMOS 45nm technology process in Cadence virtuoso environment. The design of optimal Analog and Mixed Signal (AMS) very large scale integrated circuits (VLSI) is a challenging task for the integrated circuit(IC) designer. A Ring Oscillator is an active device which is made up of odd number of NOT gates and whose output oscillates between two voltage levels representing high and low. There are a number of challenges ahead while designing the CMOS Ring Oscillator which are delay, noise and glitches. CMOS is the technology of choice for many applications, CMOS oscillators with low power, phase noise and timing jitter are highly desired. In this paper, we have designed a CMOS ring oscillator with nine stages.Previously, the researchers were unable to reduce the phase noise in ring oscillators substantially with nine stages. We have successfully reduced the phase noise to -6.4kdBc/Hz at 2GHz center frequency of oscillation.
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This paper deals with the design and performance analysis of a ring oscillator using CMOS 45nm technology process in Cadence virtuoso environment. The design of optimal Analog and Mixed Signal (AMS) very large scale integrated circuits (VLSI) is a challenging task for the integrated circuit(IC) designer. A Ring Oscillator is an active device which is made up of odd number of NOT gates and whose output oscillates between two voltage levels representing high and low. There are a number of challenges ahead while designing the CMOS Ring Oscillator which are delay, noise and glitches. CMOS is the technology of choice for many applications, CMOS oscillators with low power, phase noise and timing jitter are highly desired. In this paper, we have designed a CMOS ring oscillator with nine stages.Previously, the researchers were unable to reduce the phase noise in ring oscillators substantially with nine stages. We have successfully reduced the phase noise to -6.4kdBc/Hz at 2GHz center frequency of oscillation.
Data Types:
  • Document
The principle of the single-particle behaves exactly like a harmonic oscillator; but at very high frequency. The fixed static density is given at each end point of the particle, where between two, its acceleration would be extremely high. This anharmonic oscillation of the particle, work tirelessly between singularity and quantum decoherence.
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The principle of the single-particle behaves exactly like a harmonic oscillator; but at very high frequency. The fixed static density is given at each end point of the particle, where between two, its acceleration would be extremely high. This anharmonic oscillation of the particle, work tirelessly between singularity and quantum decoherence.
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Background: It is believed that the intensity of oscillations in the photoplethysmographic waveform variability reflects the activity of vascular regulatory mechanisms. However, the relationship of such fluctuations with the state of health is poorly understood. Purpose: The aim of our study was to assess the possibility of using spectral indices that reflect the intensity of oscillations of the photoplethysmographic waveform variability at frequencies 0.04-0.4 Hz as markers of hypertension and coronary artery disease. We did not study women to exclude the influence of menopause and sex hormones on the results. Materials and Methods: We compared synchronous 10-minute records of finger photoplethysmogram and respiration at rest in 30 healthy males (48.8 ± 4.5 years; data presented as Mean ± SD) versus 30 patients with hypertension (aged 49.0 ± 4.3 years) versus 30 patients with stable coronary artery disease (49.2 ± 4.8 years). Percentages of high-frequency and low-frequency ranges in the total power of photoplethysmographic waveform variability spectrum (HF% and LF%), and LF/HF ratio were assessed. Results: HF% are subject to by 2- to 5-fold increase in hypertensive patients (p p p Conclusion: Frequency-domain indices of photoplethysmographic waveform variability (in particular, HF%, LF%, and LF/HF) are sufficiently sensitive and specific markers of hypertension and coronary artery disease in adult males.
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Background: It is believed that the intensity of oscillations in the photoplethysmographic waveform variability reflects the activity of vascular regulatory mechanisms. However, the relationship of such fluctuations with the state of health is poorly understood. Purpose: The aim of our study was to assess the possibility of using spectral indices that reflect the intensity of oscillations of the photoplethysmographic waveform variability at frequencies 0.04-0.4 Hz as markers of hypertension and coronary artery disease. We did not study women to exclude the influence of menopause and sex hormones on the results. Materials and Methods: We compared synchronous 10-minute records of finger photoplethysmogram and respiration at rest in 30 healthy males (48.8 ± 4.5 years; data presented as Mean ± SD) versus 30 patients with hypertension (aged 49.0 ± 4.3 years) versus 30 patients with stable coronary artery disease (49.2 ± 4.8 years). Percentages of high-frequency and low-frequency ranges in the total power of photoplethysmographic waveform variability spectrum (HF% and LF%), and LF/HF ratio were assessed. Results: HF% are subject to by 2- to 5-fold increase in hypertensive patients (p p p Conclusion: Frequency-domain indices of photoplethysmographic waveform variability (in particular, HF%, LF%, and LF/HF) are sufficiently sensitive and specific markers of hypertension and coronary artery disease in adult males.
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Recent studies have reported that dim light at night (dLAN) is associated with risks of cardiovascular complications, such as hypertension and carotid atherosclerosis; however, little is known about the underlying mechanism. Here, we evaluated the effect of dLAN on the cerebrovascular system by analyzing cerebral hemodynamic oscillations using near-infrared spectroscopy (NIRS). Fourteen healthy male subjects underwent polysomnography coupled with cerebral NIRS. The data collected during sleep with dim light (10 lux) were compared with those collected during sleep under the control dark conditions for the sleep structure, cerebral hemodynamic oscillations, heart rate variability (HRV), and their electroencephalographic (EEG) power spectrum. Power spectral analysis was applied to oxy-hemoglobin concentrations calculated from the NIRS signal. Spectral densities over endothelial very-low-frequency oscillations (VLFOs) (0.003–0.02 Hz), neurogenic VLFOs (0.02–0.04 Hz), myogenic low-frequency oscillations (LFOs) (0.04–0.15 Hz), and total LFOs (0.003–0.15 Hz) were obtained for each sleep stage. The polysomnographic data revealed an increase in the N2 stage under the dLAN conditions. The spectral analysis of cerebral hemodynamics showed that the total LFOs increased significantly during slow-wave sleep (SWS) and decreased during rapid eye movement (REM) sleep. Specifically, endothelial (median of normalized value, 0.46 vs. 0.72, p = 0.019) and neurogenic (median, 0.58 vs. 0.84, p = 0.019) VLFOs were enhanced during SWS, whereas endothelial VLFOs (median, 1.93 vs. 1.47, p = 0.030) were attenuated during REM sleep. HRV analysis exhibited altered spectral densities during SWS induced by dLAN, including an increase in very-low-frequency and decreases in low-frequency and high-frequency ranges. In the EEG power spectral analysis, no significant difference was detected between the control and dLAN conditions. In conclusion, dLAN can disturb cerebral hemodynamics via the endothelial and autonomic systems without cortical involvement, predominantly during SWS, which might represent an underlying mechanism of the increased cerebrovascular risk associated with light exposure during sleep.
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Objectives: In chronic schizophrenic psychoses, oscillatory abnormalities predominantly occur in prefrontal cortical regions and are associated with reduced communication across cortical areas. Nevertheless, it remains unclear whether similar alterations can be observed in patients with a first episode of psychosis (FEP), a state characterised by pathological features occurring in both late prodromal patients and initial phases of frank schizophrenic psychoses. Methods: We assessed resting-state electroencephalographic data of 31 antipsychotic-naïve FEP patients and 29 healthy controls (HC). We investigated the three-dimensional (3D) current source density (CSD) distribution and lagged phase synchronisation (LPS) of oscillations across small-scale and large-scale brain networks. We additionally investigated LPS relationships with clinical symptoms using linear mixed-effects models. Results: Compared to HC, FEP patients demonstrated abnormal CSD distributions in frontal areas of the brain; while decreased oscillations were found in the low frequencies, an increase was reported in the high frequencies (P Conclusions: These results indicate that in addition to prefrontal cortical abnormalities, altered synchronised neural oscillations are also present, suggesting possible disruptions in cortico-cortical communications. These findings provide new insights into the pathophysiological mechanisms of emerging schizophrenic psychoses.
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Objectives: In chronic schizophrenic psychoses, oscillatory abnormalities predominantly occur in prefrontal cortical regions and are associated with reduced communication across cortical areas. Nevertheless, it remains unclear whether similar alterations can be observed in patients with a first episode of psychosis (FEP), a state characterised by pathological features occurring in both late prodromal patients and initial phases of frank schizophrenic psychoses. Methods: We assessed resting-state electroencephalographic data of 31 antipsychotic-naïve FEP patients and 29 healthy controls (HC). We investigated the three-dimensional (3D) current source density (CSD) distribution and lagged phase synchronisation (LPS) of oscillations across small-scale and large-scale brain networks. We additionally investigated LPS relationships with clinical symptoms using linear mixed-effects models. Results: Compared to HC, FEP patients demonstrated abnormal CSD distributions in frontal areas of the brain; while decreased oscillations were found in the low frequencies, an increase was reported in the high frequencies (P Conclusions: These results indicate that in addition to prefrontal cortical abnormalities, altered synchronised neural oscillations are also present, suggesting possible disruptions in cortico-cortical communications. These findings provide new insights into the pathophysiological mechanisms of emerging schizophrenic psychoses.
Data Types:
  • Document
Objectives: In chronic schizophrenic psychoses, oscillatory abnormalities predominantly occur in prefrontal cortical regions and are associated with reduced communication across cortical areas. Nevertheless, it remains unclear whether similar alterations can be observed in patients with a first-episode of psychosis (FEP), a state characterized by pathological features occurring in both late prodromal patients and initial phases of frank schizophrenic psychoses. Methods: We assessed resting-state EEG data of 31 antipsychotic-naïve FEP patients and 29 healthy-controls (HC). We investigated the 3-dimensional current-source density (CSD) distribution and lagged phase synchronization (LPS) of oscillations across small-scale and large-scale brain networks. We additionally investigated LPS relationships with clinical symptoms using linear mixed-effects models. Results: Compared to HC, FEP patients demonstrated abnormal CSD distributions in frontal areas of the brain; while decreased oscillations were found in the low frequencies, an increase was reported in the high frequencies (p<0.01). Patients also exhibited deviant LPS in the high frequencies, whose dynamics changed over increasing 3D cortico-cortical distances and increasing psychotic symptoms. Conclusions: These results indicate that in addition to prefrontal cortical abnormalities, altered synchronized neural oscillations are also present, suggesting possible disruptions in cortico-cortical communications. These findings provide new insights into the pathophysiological mechanisms of emerging schizophrenic psychoses.
Data Types:
  • Document