General Amplitude/Spectrum Measurement

Amplitude dynamic range is the difference between the maximum input level of a device and its minimum detectable signal level.

Dynamic range estimates the ability of the RF Signal Analyzer to distinguish and measure the amplitude difference of two signals. The RF Signal Analyzer can make signal measurements over a frequency range from 9 kHz to 2.7 GHz, and over an amplitude dynamic range of greater than 100 dB.

Signals of large amplitude can saturate the system and cause spurious effects. These spurs may be large enough to be mistaken for real signals. Avoid this effect by properly adjusting the amplitude of the incoming signal. Achieving proper signal levels may involve attenuating the signal before it gets to the first mixer, either by programming the internal attenuators or by using external attenuation.

The RF Signal Analyzer must be properly configured before making a measurement. A small signal can be buried in noise if the resolution bandwidth setting is too large. To measure a small signal, make sure that the input attenuators are switched off and lower the resolution bandwidth setting to reduce the noise content.

For signals below the noise floor of the RF Signal Analyzer, use an external low-noise amplifier (LNA) in front of the RF Signal Analyzer to raise the signal level. If the update speed is not fast enough to resolve a signal due to the processing demands imposed by a narrow resolution bandwidth, an LNA helps provided it does not significantly affect system linearity. For example, with a signal level of –100 dBm, set the resolution bandwidth to 1 kHz or less.