In this paper, a systematic method for the design of circuit parameters of a monolithic LC Voltage Controlled Oscillator (VCO) is reported. The method is based on the negative resistance generation technique. As a result, a VCO has been designed in 0. 18um CMOS technology using a conventional VCO structure to obtain the optimum values for the phase noise and power consumption. The simulation results prove that the proposed approach is very reliable and can be developed further for more complex structures. In this paper, the minimum phase noise of-110. 94 dBc/Hz has been obtained at 1 MHz offset frequency at the operating frequency of 10. 67 GHz. Furthermore, the designed VCO has the low power consumption of 1. 8 mW at the fundamental frequency. In addition, the designed VCO has 1280 MHz of tuning range from 9. 39 GHz to 10. 67 GHz around the central frequency of 10 GHz. Other than that, the maximum output power of the signal in the designed VCO is 6. 24 dBm.

The use of the input low-pass filter causes instability in DC-DC converters. These instabilities occur because of the interaction between the filter and the converter. In this paper, a control method based on Lyapunov is proposed. This control method uses the exact system model without linearization. All state variables are controlled using an instantaneous model. A new state variable is defined to reduce the static output voltage error. No condition is necessary to implement the control strategy. The simulation and experimental results are presented to validate the proposed control method.

Fully integrated voltage-controlled oscillator (VCO) is one of the most important blocks in the implementation of a single chip in today's wireless communication system. In this paper design and analysis of the ultra wideband and low phase noise linear LC VCO with low current consumption is presented. The MOS varactor is used to realize a wide tuning range. The phase noise level of the VCO is  -117.381 dBc/Hz at 1MHz offset and -127.2 dBc/Hz at 3 MHz offset. The Kvco ratio is about 1.24 GHz/V. The proposed topology gives a linear wide tuning range from 4.29 GHz to 5.29 GHz. Considering a 3.2V supply voltage the DC current consumption is about 3.13 mA and FOM of the proposed VCO is -187.5. This is the significant advantage of this circuit over previous works.

This work proposes a novel method to find the phase error and oscillation amplitude in multiphase LC oscillators. A mathematical approach is used to find the relationship between every stage's output phase and its coupling factor. To much more general analysis, every stage assumed to have a different coupling factor. The mismatches in LC tanks are considered as the main source of phase errors and accordingly the phase deviation of each stage is calculated in a distinct equation. Then, the amplitude of oscillation for each stage is individually derived using phase error results. Not only considering different coupling factors increases the generality of this work but also the results are in better conformance with simulations compared to previous works. The theoretical results are evaluated and confirmed through extensive simulations using ADS software.

Background: Exhaled breath condensate (EBC) could be used as a non-invasive and alternative specimen to urine and blood for monitoring propranolol levels. A simple, sensitive and selective liquid chromatography– tandem mass spectrometry (LC– MS/MS) method is employed for the determination of propranolol in EBC samples. Methods: Samples directly injected to a C18 analytical column and isocratically separated using a mobile phase composed of methanol + acetic acid (99: 1 v/v). Detection was performed by positive electrospray ionization in multiple reaction monitoring and selected ion recording modes. Results: The chromatographic separation was obtained within 6. 0 min and was linear over the concentration range of 5. 6– 224. 0 ng/mL (R2 = 0. 999). The accuracy and precision of the method were within 15% according to FDA guideline. The found concentrations of propranolol in EBC of two patients receiving 80 mg/day were 30 and 40 ng/mL. Conclusion: Developed method was applied to determine propranolol levels in three patients receiving propranolol in their medication. The obtained propranolol levels in EBC could be used to develop simpler, cheaper and more feasible analytical methods to be used in routine analysis of propranolol in biomedical analytical laboratories.