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This paper presents a novel 8.8 GHz voltage-controlled oscillator (V CO), which employs a dual-tank structure and the impulse sensitivity function (ISF) manipulation technique. By utilizing these techniques, the behavior of both the tail and the cross-coupled transistors is optimized compared to the conventional VCO; therefore, the noise from the transistors and the low quality of tank is reduced;...
This work presents a dual-band transformer-based voltage controlled oscillator (VCO) with phase noise optimization. Transformers consisting of four inductors are employed to reduce area. Four cross-coupled VCO cores are connected to the four wings of two pairs of transformers to allow individual control of the cores, whose mutual inductance is utilized to enhance the frequency tuning. Also, the capability...
A novel phase noise measurement method is proposed based on phase group processing and phase coincidence detection. Using the regularity variation of the phase difference between frequency signals, phase group processing can be made without the normalization of the frequency signals. The phase group characteristics, such as phase group synchronization, and the regularity of phase coincidence detection...
This paper presents a wide-tuning frequency generation scheme based on bottom-series coupled quadrature VCO (QVCO). The low band and middle band frequency signal is generated from the QVCO while the high band signal is obtained from a gilbert mixer. The tuning-range enhancement technique allows a three band frequency generation in the range from 2.4GHz to 8.4GHz without penalizing its phase noise...
On the basis of the conventional method, the digital techniques for temperature compensation to VCXO always deteriorate the phase noise of the VCXO badly. And the essential cause for the deterioration of phase noise is the frequent variation of control voltage to the VCXO. This paper explores a novel non real-time digital technique for temperature compensation to the VCXO, which makes the compensation...
Based on the research of the group phase relationship between two signals with different frequencies, a new PLL by directly phase comparing and locking between two signals with different frequencies (the paper following will call this new PLL DPCLDF-PLL). The application of DPCLDF-PLL on the circuit design of active atomic frequency standards, can simplify the circuit, and obtain higher performance...
High precision OCXO based on SC cut overtone crystals can show very high frequency stability and aging. However, its frequency regulation range by voltage control is not wide. When high precision OCXO is used as the standard of precise controllable measuring instruments, especially the precision slave VCOCXO, in allusion to widen frequency comparison range, the precision OCXO should not only show...
We have researched, developed and applied a series of measuring and testing technologies in the mass production and exploitation of precision frequency control devices including OCXO, TCXO, VCXO, PLL and clock modules. They have shown a key function to the performance improvement and quality guarantee of the products. In this paper we shall present turn point regulation technology and equipment of...
Phase difference measurement techniques can be used widely in positioning and length measurement, and high resolution is necessary especially for some science research purposes. In this situation the request to the measuring device is different from that to the frequency standard comparison. It is difficult to improve the resolution of conventional counting measurement method with some high-resolution...
Leeson's model (1996) is the basic model for predicting oscillator noise. The model is easy to understand and can be very useful in identifying sources and characteristics of oscillator noise. But, its main drawback lies in the fact that the amplifier gain is assumed to remain a constant versus the frequency close to the carrier frequency. Watannake (2000) describes the phase-noise characteristics...
In conventional rubidium frequency standard and some passive atomic frequency standards the voltage control crystal oscillator VCOCXO exporting the frequency signal of the standards is real time controlled. Because in the locking loop there are frequency transformation circuits, servo amplifier, testing circuits, and physics package, although the output signal of the standards is very accurate and...
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