Difference Between TCXO and OCXO

Hello Guys and Gals,

These is my first post and in upcoming weeks I will post more about Hardware Security because I love hardware. After reading these post you can gain a better understanding on the differences between these two popular crystal oscillators

Today I will tell you about a cool thing which comes with Hack-RF One (It is a Wide Band Half Duplex Software Define Radio is capable of receiving and transmitting on a frequency range of 1Mhz to 6Ghz with output power of 30 mW to 1 mW depending on the band) and it’s a TCXO chip which is know by few.

But, first let’s understand what is an Crystal Oscillator

A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material(Type of material) to create an electrical signal with a precise frequency

TCXO Chip

TCXO Stands for Temperature-Compensated Crystal Oscillator which are used to provide a higher level of temperature stability than the standard crystal oscillator (XO). TCXO provides more stability then other crystal oscillators because of these it is more likely to used in modern day devices such as smart phones, GPS and other base station applications.

Working of TCXO

TCXO is made of a element called as VCOX (Voltage Controlled Crystal Oscillator). There is a temperature sensor which will provide correct voltage to varactor (type of Diode), which then produces a frequency that is equal and opposite to the change in frequency produced by the temperature. This counterbalance-based circuitry allows the TCXO to continue to provide a stable frequency without being influenced by environmental factors such as humidity, pressure, vibration.

OCXO Chip

OCXO Stands for Oven-Controlled Crystal Oscillator which are mainly based on hypothetical theory that if you eat the crystal beyond a temperature which it would normally encounter in the working environment, then the temperature of the crystal can be maintained at a constant level (normally around 158–176°F, or 70–80°C), thus resulting in a far greater degree of frequency stability. OCXO is much more pricey then TCXO but it provides better stability and performance. OCXO are mainly used where there is requirement of precise frequency, such as controlling radio transmitter frequency, cellular based stations and military communications equipment.

Working of OCXO

OCXO is typically made from a special cut (AT- or SC-cut) and it is highly optimized for a higher internal operating temperature. A thermistor temperature sensor is used to control the power of the heater and ensure that a precise temperature within the oven is maintained constantly. The term “Oven” is thermally insulated which is enclosed and contains the crystal as well as the oscillator assembly, buffering circuitry and supply voltage regulation.

That’s all folks these was about two popular crystal which are basically used for temperature control of Hack-RF One. I hope you have liked these post so, that other Hardware Enthusiastic people can gain some knowledge from these post

Thank You

I hope you have great day