The SSA employs a cross-correlation technique to enhance the phase noise sensitivity without employing a clean reference source.
This technique essentially cancels the system noise.
The SSA consists of two independent signal paths with built-in reference sources, as well as local oscillators for signal downconversion that creates signals that are uncorrelated with each other. When the two signals are correlated and vector summed, the vector (amplitude and phase) of the two signals is emphasized. However, if two signals are uncorrelated, their vector sum is canceled, so the internal noise from references such as sources, ADCs and mixers can be canceled. The amount of noise cancellation depends on the “number” of correlation and is based on root N (the number of correlation). Correlation of 10 times produces a 5 dB noise floor improvement, and 100 times correlation produces a 10 dB improvement.Standard measurement range for the newest analyzer is 10 MHz to 7 GHz, but it can be increased to 110 GHz with currently available downconverters.
The signal source analyzer provides a one-step phase noise measurement by eliminating time-consuming procedures.
