Measuring phase noise with the E5500 phase noise test system A solution such as the Agilent E5500 phase noise test system offers the most flexibility and performance. Its capabilities are especially useful for radar because it can perform pulsed absolute and residual (or additive) phase noise measurements. It is also able to measure over a wide range of frequency offsets from 0.01 Hz to 100 MHz. As with the SSA, the E5500 is phase-detector-based but requires a separate reference oscillator. The main components of an E5500 system include a low-noise downconversion module, an external reference source, a phase noise test set (detector, PLL), a digitizer-based FFT analyzer (and/or a swept spectrum analyzer,) and PC software. Based on its modular system design, different hardware components can be used to satisfy a variety of measurement requirements. The E5500 works well in ATE applications because it is fully programmable, and because it can share common components such as the reference source and spectrum analyzer for other measurement uses. E5500 options include: absolute or residual measurements; CW or pulsed phase noise and spurious measurements; and AM noise measurements.
Pulsed DUT
Pulse generator
RF IF Reference source LO
Pulse modulator
PLL tune voltage
Pulse generator
Pulse modulator
DUT RF
Power splitter
IF Phase shifter Pulse modulator
LO
Figure 56. Test configuration for making absolute and residual pulsed phase noise measurements using the Agilent E5500 phase noise test system
Pulsed and residual phase noise measurements are especially helpful for pulsed radar systems. These measurements are available with the E5500 system but not with a spectrum analyzer-based system or SSA. Figure 56 shows a basic block diagram of the configuration used for pulsed absolute and residual phase noise measurements. Detail on how phase noise measurements are performed using the E5500 system can be found in Agilent Application Note 1309, Pulsed Carrier Phase Noise Measurements, literature number 5968-2081E. [18] 72