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Journal Radioengineering №6 for 2009 г.

Article in number:

Noise Parameters of Six-Pole Circuits

Keywords:
double-channel noise figure
six-port noise parameters
noise generator
measured error
microwave mismatch
frequency diversity
frequency conversion

Authors:

K.I. Almazov-Doljenko, S.V. Pantikin

Abstract:

The two-channel rehime of operating of a receiving device (RD) with big distance with respect to frequency between receiving channels is considered. The use of this regime yields some peculiarities at measuring its noise factor, connected with possible nonuniformity of the noise spectral power density (NSPD) of the noise generator (NG) at two different receiving frequencies, with different concordance conditions for each of these frequencies.
As standard conditions, a case when the noise source is ideally consistent with the transmission line and has uniform NSPD at various receiving frequencies is chosen. If these conditions are not fulfilled then the measuring error for the two-channel noise factor appears.
Measurement errors connected with nonideal properties of the NG are determined by two reasons:
Difference between powers from a signal source at the RD input in comparison with the ideal case;
Change of own noises value of the RD, reduced to its input, at frequencies of receiving channels under influence of the NG mismatch at these frequencies.
A receiving device with super heterodyne transformation of frequency is an active noising six-pole network, and its noise factor is a function of modules and phases of reflection factors of the input signal NG at receiving frequencies.
A more detailed description of noise properties of such devices at including them into a mismatched line is possible on the base of the further development of a system of noise parameters for noising six-pole networks

Pages: 32-34

References

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