Capturing And Measuring Microphonics And Phase-Hits With The RTSA

Introduction
Microphonic and phase-hit problems have a well-deserved reputation for disrupting development programs and stopping production lines. Many of today's modern communications systems have become very sensitive to these unintentional, internally generated sources of modulation. Compounding the problem, the intermittent nature of these disturbances has traditionally made obtaining a positive diagnosis of the cause both difficult and time consuming. The Real-Time Spectrum Analyzer (RTSA) has a unique ability to trigger and capture these elusive events for analysis, greatly reducing the time necessary to resolve the problem. Likely sources of microphonic and phase-hit problems are reviewed, with suggestions on how to identify them and characterize the components that cause them using the RTSA.

In this application note, we begin with a brief overview of the RTSA's extraordinary capabilities and an introduction to the microphonic and phase-hit problems in communications systems. We will review common causes of microphonic sensitivity, and then provide a similar review of phase-hit sources. Next, we will show how the RTSA can reliably capture these events. Finally, we will examine several methods of stimulating and characterizing the disturbances to allow the communications systems engineer to specify the required component performance to the vendors.