A Sub-Sampling Digital PM/AM Noise Measurement System
Craig W. Nelson, David A. Howe
A digital phase/amplitude modulation (PM/AM) noise measurement systems (DNMS) implementing field progammable gate array (FPGA) based digital down converters (DDCs), and 250 MHz analog to digital converters (ADCs) is reported. Measurements in the first, baseband Nyquist region shows white phase noise floors of less than - 180 dBc/Hz. With proper per-filtering of the input signals to prevent undesired aliasing, high bandwidth track and hold amplifiers (THA) extend the operating range of the DNMS to microwave frequencies. Prelliminary testing with an 18 GHz THA shows residual white phase noise floors at 10 GHz of less than - 160 dBc/Hz.
Measure: The Journal of Measurement Science
Decimination, digital measurement, DSP, FPGA, phase noise measurement