Investigations of AM and PM noise in X-band devices

Abstract

In this paper we report on measurements of phase modulation (PM) and amplitude modulation (A M) noise in a variety of amplifiers, dielectric resonator oscillator @RO) sources and mixers at 10.6 GHz. There is little information on AM noise and only limited information on PM noise in microwave devices. Two channel measurement systems and crosscorrelation analysis were used in these noise measurements. In amplificrs there are at least two random noise processes that generate equal levels of PM and AM noise when the amplifier is in the linear operating range. The noise processes correspond to a flicker noise process and a white noise process. In the DRO sources we show that these noise mechanisms are present in the active components and determine the AM and PM characteristics of the oscillator. We suggest a noise model for oscillators incorporating Leeson's PM noise lnodel and a model for AM noise in which the active components have 2 common random noise processes. We report AM noise levels of 140 dB below the PM levels at 1 Hz and typical noise floors of-169 dBc/Hz at 10 MHz. We have no evidence for AM to PM conversion in these sources. We report on noise residuals in misers from three different companies. Typical 1 Hz intercepts vary from-1 10 to-127 dBc/Hz. Noise floors are typically-173 dBc/Hz. Crosscorrelation techniques can be used to lower this value to below-190 dBc/Hz.

AM‐PM Conversion in a W‐band frequency quadrupler

“…AM noise in oscillators is often neglected and considered a minor problem. Few discussions have been published on the AM noise performance of microwave oscillators [12, 13]. Most of the literature assumes that the AM noise is much lower than the PM noise.…”

“…This seems to be the case at low offset frequencies, where flicker noise dominates. However, at higher offset frequencies the AM/PM noise ratio increases [12].…”

Low-Drift Optoelectronic Oscillator Based on a Phase Modulator in a Sagnac Loop

“…It is well known that HF/VHF Si BJTs and Si-based mixers have lower flicker noise than microwave GaAs transistors [54], [56]. Flicker noise levels of microwave GaAs amplifiers are typically 30 dB higher than that of the HF/VHF Si BJTs and 20 dB higher than that of the silicon-based mixers [57]- [59].…”

A Regenerative Frequency Comb

“…Consider an existing low noise source at f c at the input of a comb generator with spacing frequency This paper demonstrates a proof of concept comb generator, that operates in the microwave regime, using a regenerative technique, from a simple development of the concept to its implementation. The phase noise of the RCG was measured in the microwave and X bands of the frequency spectrum were conducting using analog and digital measurement techniques described in [2] [3].…”