| Precise temperature measurement is an important part of modern technology. Nowadays temperature measurement and control is carrying out through a variety of methods and tools, based on different physical principle. Traditional thermocouples and platinum resistance temperature transducers (e.g. Pt100) are still dominantly used, although semiconductor based electronic thermometers would offer a much more attractive technology with respect to direct microelectronics compatibility. However, because of the wide spread variation of semiconductor parameter values, the sensitivity of semiconductor temperature sensors varies significantly from sample to sample. This means need for an individual calibration and lack interchangeability, which cause much higher cost as expected at the first glance. The disadvantages of thermocouples are the need for an accurately defined reference temperature, low sensitivity and non-linearity.Precise thermometry, especially in the cryogenic temperature range, is compromised by the undesirable characteristics of the available sensing elements. Typical problems are non-linearity, insensitivity, self-heating, insufficient long-term stability, low signal level and dependence on magnetic fields. Because of the attractive features of quartz crystal temperature sensors as there are high sensitivity and accuracy, high dynamic range, interchangeability without recalibration, high stability, and microprocessor suiting frequency output, there have been already several attempts to develop respective measurement devices in micro sensor filed.A new type miniature thermo-sensitive quartz tuning-fork resonator using a new thermo-cut a doubly YZtw (110710°) cut with frequency output had been designed. Its working at flexural mode was better than at others. Meanwhile, the way for raising SNR and reducing equivalent resistor of the sensor were analyzed in theory. A change building way has been carried out to form and adjust the precise frequency, which improve sensitivity and reduce non-linearity. It is very suitable for temperaturesensor.Take use of the theory of equal-precision digital frequency measurement (EPDF) to build the hardware of the intelligent quartz temperature sensor (QFTS). By use of a counter with an appropriate time base, since counting is digital operation, with the elimination of analog-to-digital conversion, these QFTS transmit their inherent sensor performance undiminished by the intermediate circuitry. The use of counter as an analog-to-digital converter (ADC) has an important advantage: the costs increase only slightly with the number of digits; the obtainable dynamic range, the ratio of measurement range over resolution, is not limited by the analog-digital conversion. In the case of frequency sensor the dynamic range is only limited by the sensor principle itself (resolution up to lO^C). The theory of EPDF, error analyzed, improves precision and resolution is presented in this paper.The characteristic frequency-temperature (TFC) of (QFTS) has been analyzed. The QFTS has long-term stability and good interchangeability, which is less frequency recalibration. The method of the QFTSs characteristics linearization with regression algorithm was used. This typical of methods are segmentation lineation interpolation and polynomials interpolation. Using methods, the higher precise can be achieved, but it needs the larger memory and accuracy temperature calibration that its no suitable for embedded system, so QFTSs characteristics is produced with least mean squared polynomial fitting. Its sample, quick speed and less memory, so its suitable for embedded system.Finally, the experiments show QFTS for use from -40°Cto 160°C with resolution of 0.005 °Cand with accuracies of 0.1 °C for 2-s response time.
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