Agilent Technologies 346A Manual do Utilizador descarregar pdf (Página 10)

Device under test (DUT)

Your DUT contributes to the overall noise ﬁ gure uncertainty based on its

individual noise ﬁ gure, gain, port match, and noise parameters. In general,

there are two scenarios to consider when choosing the Y-Factor method. When

the output noise of the DUT is well above the input noise of the analyzer, the

analyzer with the best instrument uncertainty gives the most accurate results,

and the MXA signal analyzer is the best option. If the output noise of the DUT is

smaller, select the NFA noise ﬁ gure analyzer, which gives the lowest uncertainty.

Refer to Table 2 for nominal speciﬁ cation comparison of these solutions at 1 GHz.

The following graph shows how DUT gain affects noise ﬁ gure uncertainty when

using a spectrum analyzer or noise ﬁ gure analyzer. This example is at 1 GHz with

a 346A noise source and assumes the DUT has a 2 dB noise ﬁ gure and 1.5:1 VSWR.

Figure 3. As the gain of a DUT decreases, Y-factor noise ﬁ gure measurement uncertainty increases;

below 10 dB of gain, there are signiﬁ cant differences between the various instrument choices

The values in the graph above were created via the noise ﬁ gure uncertainty

calculator and nominal speciﬁ cations at 1 GHz shown in Table 2. The uncertainty

calculator can be found at www.agilent.com/ﬁ nd/nfu. The uncertainty calculator

can be used for either of the following cases:

Modeling the performance of your system: For this purpose, defaults are available

for Agilent's noise ﬁ gure instruments and noise sources. These defaults have typical

values associated with them and can be useful for estimating the effect individual

parameters have in overall uncertainty levels.

Making actual calculations of the uncertainty of your system: You will need to

obtain accurate values of all the associated parameters in question, such as match

and gain. Please consult the calibration certiﬁ cates of your instruments to obtain the

measured uncertainty parameters of the equipment being used.

Find out more www.agilent.com/ﬁ nd/nf

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 ... 21 22

Sem comentários

Agilent Technologies 346A Manual do Utilizador Página 10