Phase Noise Measurement System Research Articles

Investigation of Phase Noise Generation in Microwave Electron Devices Operating in Nonlinear Regime Exploiting a Flexible Load– and Source–Pull Oscillating Setup

In this paper, we present a flexible measurement setup for the characterization of the phase noise (PN) and frequency stability of microwave electron devices operating under nonlinear oscillating conditions. The setup embeds the device-under-test (DUT) within a feedback loop, and forces it into a large signal (LS) oscillating regime, by controlling the loop amplitude and phase. The DUT input and output terminations are also controlled, by exploiting load- and source-pull capabilities. By exploiting this setup, we demonstrate that the PN performance of microwave oscillators can be strongly affected by the device nonlinear RF working regime. As well known, the oscillator PN is mainly related to the frequency stability of the circuit and the active device low-frequency noise up-conversion to RF mechanisms. By using measurements performed with the proposed setup, it is shown that these aspects depend also on the device LS operating conditions; hence, the dynamic LS load line and the amplifying class of operation have a significant role for the oscillator PN. The experimental results described in the paper, along with the analyses proposed by using simulations, are in accordance with recently published nonlinear noise modeling approaches based on cyclostationary noise sources. The investigation performed by means of the setup can provide information for both the design of low-phase-noise (LPN) oscillators and the parameter extraction and validation of nonlinear noise models of electron devices. Furthermore, this setup is also proposed as a tool for the evaluation of power amplifier PN when a dedicated residual phase noise measurement system is not available.

Improved phase noise for dielectric resonators oscillators with broadband tuning

AbstractIn this article, we describe a method of design of very low phase noise dielectric resonators oscillators at 13 GHz. By using two Silicon Germanium transistors with total gains 8 dB and lower flicker noise corner between 10 kHz and 40 kHz, the phase noise of the oscillators can be achieved −125 dBc/Hz at 10 kHz offset. The resonator has unloaded Q around 14,000 at operating frequency and is then optimized and coupled to the amplifiers for minimum phase noise where QL/Q0 = 1/2 hence S21 = −6 dB. To incorporate tuning, phase shifter is also investigated. The phase noise measurement system is also presented using two identical oscillators phase locked at the same frequency.© 2009 Wiley Pe riodicals, Inc. Microwave Opt Technol Lett 51: 1312–1316, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24334

Ultra-stable crystal ovens and simple characterisation

New double ovens have been designed to improve the ultimate noise floor of a crystal phase noise measurement system. Their thermal stability characterisation is given.

Passively mode-locked waveguide laser with low residual jitter

Picosecond pulses at 1.53 /spl mu/m with low residual jitter are generated from a passively mode-locked erbium/ytterbium codoped planar waveguide laser in an extended cavity configuration. The round-trip frequency of the laser cavity is actively referenced to the frequency of a stable electronic oscillator; this lowers the residual root-mean-square timing jitter to 83 fs over the frequency range of our phase-noise measurement system 100 Hz-10 MHz.

Phase noise measurements of a D-band backward wave oscillator

The difficulties encountered in measuring phase noise at millimetre wave frequencies have resulted in a scarcity of such data for backward wave oscillators. This paper reports the extension of a highly sensitive quasi-optical phase noise measurement system to D-band and presents phase noise spectra of a commercial backward wave oscillator at carrier frequencies between 120 and 160 GHz for offset frequencies in the range 10 kHz to 10 MHz. At small offset frequencies, the measured phase noise is typically 15 dB higher than solid state oscillators at this frequency. >