Precision OCXO Oscillator | oven-controlled crystal oscillator

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.

Why Choose Morion OCXO?

  • Best Temperature Stability                                        10 MHz DOCXO Temp Stability Available:
    OTR of -400C to +850C @ >±1E-11
  • Best Short-Term Stability (ADEV)
    10 MHz OCXO ADEV Available:
    1 second @ 1.5E-13
    10 seconds @ 2.5E-13
    100 seconds @ 4.5E-13
  • Best Noise Floor
    100 MHz OCXO Noise Floor Available:
    >100 kHz off set @ -183 dBc/Hz 
  • Best Close-In Noise
    10 MHz OCXO Close-In Phase Noise Available:
    0.01 Hz off set @ -40 dBc/Hz
    0.1 Hz off set @ -97 dBc/Hz
    1.0 Hz off set @ -120 dBc/Hz

Precision OCXO Oscillator Characteristics


Phase Noise

1) Temperature Stability
Temperature stability is an important, if not the most important 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 off ers the world’s best performance
of ±1E-11 over the -40C…+850C operating temperature range.

2) Short Term Stability-ADEV
Allan Deviation (ADEV) is the probability of frequency change/drift over
a short period of time, 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

3) Aging
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.

1) Close-In Noise
Close-in noise is the phase noise measured at 0.1 Hz to 100 Hz off set
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 close-in phase noise performance than higher frequency OCXOs (i.e. 10 MHZ versus 100 MHz).

2) Intermediate Noise
Intermediate noise is phase noise measured at >100 Hz off set from the
OCXO’s carrier frequency to the point the phase noise curve flattens (generally ~1KHz to 10kHz off set 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 diff rent value components in the oscillator circuit.

3) Noise Floor
Noise floor is the area on the phase noise curve after it flattens, generally
>10 kHz off set from the carrier frequency. It is important contributor to the signal-to-noise ration of a receiver circuit and test equipment.

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 Oscillators
OXCO oscillators come in different shapes and sizes for different application and products. OXCO is predominantly used in satellite, telecom
and other devices where a high degree of stable frequency reference is required. 

As a reference, there two other types of oscillators. The Voltage Controlled and Simple Oscillators (VCXOs & XOs) which is used in mobiles phones and Temperature Compensated Oscillators, TCXO to handle large variations in ambient temperature.

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.

About Morion

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 to with your specifications.