4 research outputs found

    Improving radar performance with constant envelope multi-level chirp

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    M-level Continuous Phase Chirp Modulation is considered for data transmission. In this article, we would like to propose a new approach to transmitting information with the help of multi-level wave guide signaling. The main problem with the classic chirp modulation system is that the final phase of the signal is not equal in each period to the initial phase of the next step, and this discontinuity is present in each data transmission period. The main objective of this paper is to improve the efficiency of chirp modulation, which is recommended for continuous phase multi-level scalar modulation, which results has a significant increase in system performance. In this new approach, for sending the M symbols, we use the M level to send the message. With the help of this idea, we simulate the telecommunication system and examine the probability of its bit error in the presence of additive white Gaussian noise and Rician fading

    A comparison study of lipid profile levels between skin tags affected people and normal population in Tehran, Iran

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    Background: For many years the association of skin tags and endocrynopathies has been postulated, although many reports are available but it has never been evaluated to mean normal population. Dyslipidemia is a frequent disorder among people and seemed to be necessary for screening within skin tag condition. This study is designed to find any possible association between skin tags and dyslipidemia. Materials and Methods: From April 2009 to June 2011, 168 patients enrolled the study. Among the remaining 152 patients, there were 89 females (58.5%) and 63 males (%41.5). Based on the TLGS study 136 men and 220 women enrolled the control group of study. The mean age was 28.4 years. Patients trained to have normal free diet for at least 1 month then referred to the laboratory. Blood samples were taken over 12 hours fasting with 2 hours intervals. Hypertriglyceridemia was defined as plasma level ≥160 mg/dl for men and ≥130 mg/dl for women. Hypercholesterolemia pointed at its value >200 mg/dl. Normal HDL levels was defined as >39 mg/dl for men and >35 mg/dl to women. Results: Mean skin tag number was 12.6 per subject. The most frequent localizations of skin tags were neck and upper chest (mean number: 13.4, 48.9%) followed by axilla (mean number: 11.6, 33%) and breast (10.2, 10.1%) in the patient group. The mean cholesterol level of case group was 192.2 ± 33.1 mg/dl, while it was 187.0 ± 42 mg/dl in the control group). The mean ± SD for triglyceride was 132.1 ± 69 mg/dl in comparison to 129 ± 74 in the control group. Conclusion: The study showed no significant differences between normal population and patients′ lipid profile
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