EMXOs boost oscillator performance with lower power consumption and reduced size
Sep 1, 2007
By Dave Bail Advances in the evacuated miniature crystal oscillator (EMXO) manufacturing process have enabled EMXOs to achieve performance comparable to oven-controlled oscillators with lower power consumption and lower cost. While describing the performance of EMXOs, this article discusses its benefits in satellite applications and provides a design example....
Direct digital synthesis enables digital PLLs
Jul 1, 2007
By Paul Kern Direct digital synthesis, together with a DAC and a high-performance digital
phase detector, overcome several fundamental drawbacks in analog PLLs, such
as asymmetry in the phase detector or bandwidth limitations and phase noise in
the VCO. Furthermore, because the circuitry is digital, feedback-loop parameters
are adjusted by changing numerical coefficients in device registers rather than
changing electrical parameters in physical components, the latter process being
especially difficult for ASIC designs....
How to determine an effective damping factor for a third-order PLL
Jun 1, 2007
By Ken Gentile A clever means for calculating without using circuit simulations is presented. The advantage is that a relatively dense plot (55 points) of vs. phase margin can be produced in a matter of seconds....
Arrival-time detection reduces PLL jitter
Feb 1, 2007
By Wen Lin Careful attention to delay matching and harnessing the properties of metastability in logic circuits can stabilize the output of a single-ended charge pump, thereby reducing voltage-controlled oscillator phase noise in a phase-locked loop....
Silicon timing clocks are getting sophisticated
Oct 1, 2006
Ashok Bindra, Editorial Director Whether it is a microprocessor-based control circuitry, RF transceiver for wireless communications, or a linecard for optical networks, clocks are needed as timing circuits to perform functions like synchronization, distribution, control and protection. They are critical components when it comes to overall system performance. Over time, these simple discrete components have become quite sophisticated....
Design and performance of precision miniature TCXOs
Sep 1, 2006
By Steve Fry This article will describe the current state-of-the-art in TCXO temperature-compensation
technology and the associated crystal resonators....
Low power, giga speed programmable divider in 0.18 m CMOS
Jul 1, 2006
By Girish N. Jadhav This article will focus on the design and simulation of a new programmable divider architecture for use in the 2.412 GHz to 2.484 GHz frequency bands....
Impact of ultralow phase noise oscillators on system performance
Jul 1, 2006
By Ramon M. Cerda While helping to understand phase noise and jitter of high-performance oscillators, this article also examines the impact of oscillator phase noise on system performance, underscoring the importance of using ultralow phase noise oscillators in systems....
PLL frequency synthesizer handles 8 GHz
Jun 1, 2006
Analog Devices integrated 8 GHz phase-locked loop frequency synthesizer is the RF Design Product of the Month for June 2006....
Simulating PLL reference spurs
May 1, 2006
By Steve Williams and Tony Caviglia Spurious levels on the output of a phase-locked loop that generates a carrier signal are an important specification in many RF systems. Spurs may come from a variety of sources, but oneof the most common is the PLL's reference clock....
Changes in Base Station Backhaul Drive New Sync Solutions
Nov 1, 2005
By Barry Dropping As more mobile network operators deploy high-speed data services using IP
backhaul, the need for stable and accurate frequency reference becomes more
critical. This need is particularly apparent for applications such as successful
hand-offs between base stations and the transport of real-time services....
Novel High-Frequency Crystal Oscillator Cuts Jitter and Noise
Jun 1, 2005
By Dan Nehring The inverted Mesa resonator offers a high-performing alternative to SAW-based
oscillators and other bulk resonator types, which use a noisy PLL or other such
parametric multiplier that also multiplies noise. Oscillators have been developed
to demonstrate the effectiveness of this design technique....
Specifying a quartz crystal for a VCXO
Aug 1, 2004
By Ramon M. Cerda A popular application for the voltage-controlled crystal oscillator is the forming
of a phase-locked loop. Designing the VCXO for this application requires a
‘pullable’ quartz crystal....
Pierce-gate oscillator crystal load calculation
Jul 1, 2004
By Ramon Cerda The Pierce-gate oscillator is well recognized by most designers, but few understand how to specify the crystal correctly. The crystal used can be either a fundamental AT-CUT or BT-CUT. A BT-CUT crystal has poor frequency stability over temperature compared to an AT-CUT. This topology uses a parallel crystal and not a series crystal....
Data timing is critical in distributed systems
May 1, 2004
By Fred Mohamadi A distributed system consists of autonomous computing and processing nodes linked together as a network. It is supported by software and hardware that...
