• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.10
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• pp.727-732
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• 2004

TCXO is one of the most important component in communication systems. We present a analytic method approach to design the Temperature Compensated Circuit. The conventional method for extracting the circuit parameters, which are for thermistor, Colpitts and frequency control circuit is the trial and error correction. In this paper, we analyse the temperature compensating circuit to extract TCXO circuit parameter. In order to show the validity of this paper, we have designed and implemented the 10MHz TCXO. The fabricated TCXO shows 1ppm frequency drift characteristic over the temperature range of -40℃∼85℃.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.8 s.350
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• pp.6-12
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• 2006

Recently, according to the rapid development of mobile system, the development of relative mobile components has been required, and especially, with the miniaturization of mobile component, the complex with nearby components has been progressed. In this paper, multi-output VC-TCXO (Voltage Controlled-Temperature Compensated Crystal Oscillator) for WCDMA integrates the additional CMOS inverter, so it can be the normal clipped sinewave output and additional CMOS output, and also it can be satisfied the VC-TCXO's requirements for WCDMA system. And the important characteristics of reference oscillator, like phase noise and frequency short term stability, are satisfied with WCDMA(UMTS) system's requirement In this paper, however, 25MHz is used for reference frequency, similarly and practically, we think that it can be used from 10MHz to 40MHz.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.841-844
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• 2005

Multi-output VC-TCXO (Voltage Controlled-Temperature Compensated Crystal Oscillator) for WCDMA has integrated the additional CMOS inverter, so it can be normal clipped sinewave output and additional CMOS output and it can be satisfied the VC-TCXO Characteristics that WCDMA system required. In this paper, however 26MHz is used for reference frequency, similarly and practically, it is usable from 10MHz to 40MHz, Most important factor to integrate CMOS inverter internally is the isolation between normal output and additional output. For this, it is separated in package design, due to this, when it isn't used additional output, it shows the same electrical performance, when it is used additional output, it has minimum-rized the interference. and then the important characteristics in reference oscillator are met to WCDMA system's requirements, like phase noise and frequency short term stability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.5
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• pp.739-745
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• 1993

In mobile communication instruments, realization of the frequency synthesizer with high stabililty in temperature is very important. In order to realize a high stability frequency synthesizer, the oscillator providing for reference frequency must be stabilized in various temperature. In accordance to this requirement, the TCXO using digital method is rrealized in this thesis. The DTCXO consists of temperature sensing part, control part and the VCXO. The frequency stability of the realized DTCXO is 0.94 ppm on average. This is an improved result when compared with the 2.5 ppm of the TCXO using analog method.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.33-36
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• 2001

An automatic TCXO frequency-temperature test apparatus was firstly developed by using thermoelectric device may. The developed system swing stably the test temperature range from -40$^{\circ}C$ to +80$^{\circ}C$ for about 1 hour The rising temperature ratio was fairly linear with time in this test temperature range. The temperature could be controlled error in error range of ${\pm}$0.05$^{\circ}C$ in this system. The frequency-Temperature properties of TCXO or the thermoelectric properties of other electric device.

• Journal of Korean Electronics
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• v.24 no.7
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• pp.56-57
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• 2004

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.05a
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• pp.94-94
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• 1998

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.109.3-109
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• 1998

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.33.3-33
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• 2002

Pseudolite (PL) is a kind of signal generator, which transmits GPS-like signal at the ground. However our own made PL is different from a GPS satellite in clock accuracy. GPS satellites are synchronized by use of high precision atomic clocks. But because our PLs use low cost temperature controlled oscillators (TCXO), so it is very difficult to synchronize them. Hence, we should install reference station and use Differential GPS (DGPS) algorithm to calculate user position. By use of this method, we already developed indoor navigation system a few years ago. We named it as 'Asynchronous Pseudolite Indoor Navigation System'. However, this system requires that sampling times of all the receivers...

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1200-1203
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• 2002

A temperature compensated Crystal Oscillator is widely used for the stable frequency source of mobile communication equipments. Recently, it has become necessary to reduce power consumption of TCXOs. In this paper, we have proposed a TCXO using weak inversion MOS transistors and have evaluated its fundamental characteristics.