Residual phase noise measurements of VHF, UHF, and microwave components

Abstract

The results of residual phase noise measurements on a number of VHF, UHF, and microwave amplifiers, both silicon bipolar junction transistor (BJT) and GaAs field effect transistor (FET) based, electronic phase shifters, frequency dividers and multipliers, etc., which are commonly used in a wide variety of frequency source and synthesizer applications are presented. The measurement technique has also been used to evaluate feedback oscillator components, such as the loop and buffer amplifiers, which can play important roles in determining an oscillator's phase noise spectrum (often in very subtle ways). While some information has previously been published related to component residual phase noise properties, it generally focused on the flicker noise levels of the devices under test, for carrier offset frequencies less than 10 kHz. The work reported herein makes use of an extremely low noise, 500 MHz SAW resonator oscillator (SAWRO) test source for residual phase noise measurements, both close-to-and far-from-the-carrier. Using this SAWRO test source at 500 MHz, we have been able to routinely achieve a measurement system phase noise floor of -184 dBc/Hz, or better, for carrier offset frequencies greater than 10 kHz, and a system flicker phase noise floor of -150 dBclHz, or better, a t 1 Hz carrier offset. The paper discusses the results of detailed residual phase noise measurements performed on components using this overall system configuration. Several interesting observations related to the residual phase noise properties of moderate to high power RF amplifiers, i.e.. amplifiers with 1 dB gain compression points in the range of +20 to +33 dBm. are highlighted.

Prediction of phase noise in 2.4GHz SAW oscillator with surface transverse wave resonator

“…The residual phase noise measurement techniques [7] are employed to evaluate the components of loop amplifier, STW resonator and electronic phase shifter. The noise floor of the measurement system is about -170dBc/Hz with 1/f flicker noise corner at 17kHz offset.…”

A model for phase noise generation in amplifiers

“…The baseband shaping of the low frequency noise may explain the anomalous "bumps" observed in [10]. It has been shown that, although the signal frequency may be relatively high, the appropriate circuit models must be used to predict baseband shaping accurately.…”

Investigations of AM and PM noise in X-band devices

“…As in the amplifier case, we find that there is often a l/f component of AM and PM noise of nearly equal amplitude. Close to the camer the l/f3 PM noise dominates as is generally accepted [2,4,8]. There has been speculation that PM to AM conversion with the oscillator would cause the AM noise close to the carrier to vary as l/f3.…”

“…Specific samples often deviate from the models, but they still give us a better insight into the total noise process within the device. The noise model for X-band double balanced mixers is similar to that of rf mixers [4,5]. The noise models for amplifiers are, to our knowledge, the first to show that the PM and AM noise added by an amplifier originates from two common sources.…”

“…Around 10 MHz from the carrier, the PM noise is white at -173 dBc/Hz. This white noise originates from the thermal PM noise of an amplifier [4,5] given by the expression where k is Boltzmann's constant, T the temperature in degrees kelvin, F the noise figure of the amplifier, G(f) the gain of the amplifier, and Po the output power of the amplifier. For this amplifier the noise figure is -3 into two similar channels for AM noise detection.…”