Rho (Custom IQ)

Rho is reported for QPSK Quadrature phase shift keying and OQPSK Offset Quadrature Phase Shift Keying: A type of QPSK modulation that offsets the bit streams on the I and Q channels by a half bit. This reduces amplitude fluctuations and helps improve spectral efficiency. formats. It is similar to error vector magnitude (EVM) and is a measure of the quality of digital modulation. Rho is computed by comparing the normalized correlated power between the measured signal and the reference signal and is designated as the waveform quality factor. The maximum value of Rho is 1.0 (which means the measured signal and reference signal are 100% identical).

A Rho value of 1.0 indicates that all of the transmitted power correlates with the ideal signal as determined by the detected sequence.

For Custom IQ demodulation, Rho is the correlated power of a single channel (for example, the pilot channel in IS-97).