Anyone who have designed a capacitively tuned VFO/VCO with the wide tuning range (>1.5-2x) has noticed that the oscillation threshold changes substantially with the tuning frequency. The usual solution to the problem is a combination of: 1. the AGC circuit, most frequently via the amplifier bias that changes the amplifier conduction angle; 2. shunting the LC circuit with a damping resistor or b...

in this paper a fast and novel stability-indicating ultra fast lc method for separation and estimation of impurities in clopidogrel and aspirin in their combined tablet dosage form and omeprazole was developed. the separation of usp related substances of clopidogrel (a, b and c), aspirin (d), omeprazole (a, b and c) and few other unknown impurities was detected by using ultra fast liquid chroma...

This series of articles discusses oscillator phase noise reduction techniques and gives specific resonant circuit solutions using lumped and distributed parameters for both frequency stabilization and phase noise reduction. These topics are covered in Part 1. Phase noise improvement can also be achieved by appropriate low-frequency loading and feedback circuitry optimization. The feedback syste...

This paper presents an inductive coupling interface using a relay transmission scheme and a low-skew 3D clock distribution network synchronized with an external reference clock source for 3D chip stacking. A relayed transmission scheme using one coil is proposed to reduce the number of coils in a data link. Coupled resonation is utilized for clock and data recovery (CDR) for the first time in t...

This paper demonstrates the feasibility of implementing wide tuning band low phase noise oscillators in low cost Sibased integration technologies. For that, it is necessary to use radio-frequency switched capacitors arrays (RFSCA) and differentially tuned anti-parallel varactors. To corroborate this idea, a voltage controlled oscillator (VCO), designed in a low cost 0.35 μm CMOS technology, is ...

of any wireless communications system. Due to their low cost, design simplicity and ease in practical implementation, for example, MOSFET-based oscillators are widely used in modern wireless handset applications. This three-part tutorial highlights the basics of the oscillator circuit design, setting the relationships between the start-up and steadystate operating modes and the device equivalen...

This paper describes 3-GHz and 7-GHz tunableinductance LC-tank voltage-controlled oscillators (VCOs) implemented in 0.18-μm CMOS technology. Unlike the traditional tuning method by a varactor, a tunable inductor is employed in the VCO by using a transformer to compensate for the energy loss. The VCO facilitates the tuning frequency and low noise of the output signals, together with a variable i...

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tailed discussion and analysis of the start-up and steady-state oscillation conditions for transistor LC oscillators with emphasis on CMOS devices. Part II presents both linear and nonlinear phase noise models for the parallel feedback and negative resistance oscillators. Each approach to the oscillator phase noise calculation has its own advantages and drawbacks. For example, the linear Leeson...