Agilent Technologies E8267C PSG Manual de usuario descargar pdf (Pagina 8)

Figure 6. Conventional analog setup to perform a multitone IMD measurement.

Although this approach has been used for many years (primarily due to a lack of reasonable

alternatives), this is a relatively complicated test setup with a high overall cost of test.

Like with the two-tone test setup, it is important to ensure there is adequate isolation

between the individual CW signal generators so that they do not intermodulate with

each other prior to the input of the DUT.

The main shortcoming associated with this test setup is the inability to systematically

initialize the phase of the CW signal generators. Monitoring the variability in IMD

performance on a spectrum analyzer over a period of 5 to 10 minutes reveals that the

phase relationships of the CW signal generators do change over time. As previously

discussed, this is desirable for gathering IMD results from different phase sets. However,

the CW signal generators drift relatively slowly with respect to one another and cannot

be systematically initialized. Consequently, the conventional analog approach requires

too much time to obtain test results that are statistically representative of real world

operating conditions.

Isolator

AMP

LPF

Attenuator

DUT

PSA spectrum analyzer

Combiner

External equipmentBank of PSG CW signal generators

1 2 3 4 5 6 7 8 9 10 11 12 13 ... 19 20

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Agilent Technologies E8267C PSG Manual de usuario Pagina 8