The ability to achieve level accuracy that provides meaningful measurement results depends on external leveling techniques that correct for mismatches and frequency- response variations. In most cases, a combination of static and dynamic leveling is the most effective approach.
Static leveling relies on an array of usercreated calibration factors that ensure the delivery of flat power at an interface beyond the signal generator’s RF output connector. The calibration array can be generated by a power meter under the control of the signal generator. The two instruments step through a list of key frequencies, generating and measuring the associated power levels. The signal generator interpolates values for in-between frequencies.
External dynamic leveling uses either a power meter or a crystal diode detector. The key difference is a tradeoff between speed and accuracy. The power-meter-based approach is more accurate, while the diodebased approach is faster.
Working in concert, the static flatness correction removes frequency-response errors, including those from the coupler and diode detector. The dynamic leveling will correct for mismatches that vary with frequency and signal level.