Precision OCXO Oscillator
What is an OCXO?
Precision OCXO Oscillator. Oven-Controlled-Crystal-Oscillator (OCXO) is a reference oscillator having excellent temperature stability and low phase noise. These are the key parameters of an OCXO.
OCXOs utilizes a small, highly accurate oven to improve frequency stability versus ambient temperature. To further improve temperature stability, the OCXO uses a precision SC-cut crystal in the oscillator circuit.
With the SC-cut crystal, the OCXO also provides excellent phase noise in the “close-in,” intermediate, and “floor” offset ranges as compared to other commercially available reference oscillators.
OCXOs are used in telecommunication, test, and measurement network synchronization and other applications the require a reference oscillator with precision stability and excellent phase noise. OCXOs are generally not used in commercial electronics due to cost constraints.
- Temperature Stability
Temperature stability is essential, if not the most critical parameter of the OCXO. Typical temperature stability performance is ±1E-9 over the range of -200C to +700C. This 100 times better than Temperature-Controlled-Crystal-Oscillators (TCXO). Morion offers the world’s best performance of ±1E-11 over the -40C…+85°C operating temperature range.
- Short Term Stability-ADEV
Allan Deviation (ADEV) is the probability of frequency change/drift over a short period, usually ranging from 0.1 seconds to 100 seconds. This is important for measuring or conducting short term events. It should be noted that temperature stability must be considered while specifying ADEV.
1.5E-13 @ 1 second
2.5E-13 @ 10 seconds
4.5E-13 @ 100 seconds
Aging is frequency drift/change over time, generally one day, one year, or ten years. Aging is determined by the purity of the crystal, and the quality of the components used in the oscillator circuit. Generally, OCXO aging performance is 1…5E-8/year, which translates to approximately 1…5E-10/day. While aging is important, most applications employ a GPS-PLL circuit to correct aging/frequency drift.
- Close-In Noise
Close-in noise is the phase noise measured at 0.1 Hz to 100 Hz offset from the OCXO fundamental frequency. It is important for high data rate transmission and test & measurement. Close-in noise generally correlates to ADEV. Both are highly dependent on crystal quality and crystal surface integrity. Lower frequency OCXOs have better closw-in phase noise performance than higher frequency OCXOs (i.e. 10 MHZ versus 100 MHz).
10 MHz OCXO Close-In Phase Noise Available:
-40 dBc/Hz @ 0.01 Hz offset -97 dBc/Hz @ 0.1Hz offset -120 dBc/Hz @ 1 Hz offset -145 dBC/Hz @ 10 Hz offset -157 dBc/Hz @ 100 Hz offset
- Intermediate Noise
Intermediate noise is phase noise measured at >100 Hz offset from the OCXO’s carrier frequency to the point the phase noise curve flattens (generally ~1KHz to 10kHz offset from the carrier. Intermediate phase noise is generally more important for higher frequency (100 MHz) OCXOs and is determined primarily by the components used in the oscillator circuit. Indeed, it can be “shaped” using different value components in the oscillator circuit.
100 MHz OCXO Intermediate Phase Noise Available:
-140 dBc/Hz @ 100 Hz offset -165 dBc/Hz @ 1 kHz offset -176 dBC/Hz @ 10 kHz offset
- Noise Floor
The noise floor is the area on the phase noise curve after it flattens, generally >10 kHz offset from the carrier frequency. It is an important contributor to the signal-to-noise ratio of a receiver circuit and test equipment. The noise floor is generally more important for higher frequency (100 MHz) OCXOs and is determined by the noise factor of components used in the oscillator circuit and output buffer amplifier. Morion has proprietary technology/techniques that result in a 100 MHz OCXO noise floor of >-180 dBc/Hz.
Other Important Morion OCXO Features
Available as RoHS
Low G-sensitivity available
Small size and low power consumption options
Extremely competitive pricing
More About Precision OCXO Oscillator
OXCO oscillators come in different shapes and sizes for various applications and products. OXCO is predominantly used in satellite, telecom, and other devices where a high degree of stable frequency reference is required.
While frequency stability and phase noise are the key performance parameters of an OCXO, one must consider unit size, current consumption, and certainly cost. In some applications, G-sensitivity should be reviewed.
Morion is a globally recognized provider of high-performance precision OCXOs and can meet most requirements of any application. Morion will be happy to assist with your specifications.