The temperature stability of temperature compensated crystal oscillators is much superior to normal crystal oscillators thus TCXOs are used in the applications where high frequency source is required within a small space and at reasonable cost. Although crystal oscillators are amongst the highly stable oscillators, they are nevertheless affected by temperature. The cut of the actual crystal element can minimize the effect of temperature, but still they are affected to some degree. The effect of the temperature can be defined thus it is possible to compensate for many of these effects.
Temperature compensated crystal oscillator,
TCXOs is the oscillator that provides much higher temperature stability than a normal crystal oscillator. TCXOs adjust the frequency of the oscillator to compensate for the changes that happen as a result of change in temperature. TCXOS is incorporated with voltage controlled crystal oscillator (VCXOs) that helps to adjust the frequency which is connected to a circuit that senses the temperature and applies a small correction voltage to the oscillator.
Nowadays, varieties of temperature sensing and compensating networks are used. More recently digital techniques such as DSP have been used to get highly accurate compensation network. However, there is a problem with applying the temperature compensation in a TCXO. The temperature coefficient of the crystal changes with temperature which is not linear thus making the design of the compensation network quite complicated.
In terms of performance TCXOs is much better that that of a normal
crystal oscillator. The figures with in the range of 1 to 5 are often achieved. However, some of the figures are due to frequency or temperature hysteresis. Also, the power dissipation of TCXOs is greater than an ordinary oscillator. TCXOs are available in variety of packages on the basis of its design and requirement of the client. By utilizing ASIC technology, it enables much smaller packages to be used.
TCXOs are widely used where accurate frequency sources are needed. They are reasonable and smaller than OCXOs, therby making them an ideal solution for many portable units. There are several TCXOs manufactures in the market that can help you to select or design the right TCXOs for your application. Choosing oscillators can prove to be quite overwhelming, therefore visiting the right oscillator manufacturer who can guide you and suggest the pros and cons completely is quite essential for the success of your application.
