10 MHz TCXO Stable Time Base
Created: Oct 05, 2015
No description available.
The stable time base has been widely used especially in satellite communications systems. It provides precise frequency accuracy and improved close-in phase noise performance for GPS and other related devices. With the frequency oscillator continuously powered, a couple timing errors can be avoided. The device uses the Connor Winfield’s T602-010.0M crystal oscillator that has an exceptional frequency stability and low phase noise. It is capable of holding Stratum 3 level temperature stabilities of ±0.28 ppm.
In the circuit, the 10MHz output signal of the TCXO will be buffered with a simple 2N2222A transistor and sent to a 74HC390 dual-decade ripple counter to be divided down for generating an optional 1MHz reference signal. The final two signal outputs are isolated with a 74HC241 octal 3-state buffer. The signals are then routed to front-panel BNC jacks. A few series 100ohm resistors limit the current in case any of the outputs get shorted.
The high-stability time base is essential for precise frequency accuracy and improved close-in phase noise performance. The enhanced phase noise performance is beneficial for a variety of applications, including high order modulation schemes like 64 and 128 QAM, LO substitution, jitter measurements, IEEE 1588 applications, Synchronous Ethernet slave clocks, ITU-T G.8262 EEC options 1 & 2, compliant to Stratum 3, GR-1244-CORE & GR-253-CORE , Wireless Communications and GPS.