Noise Measurement Group Operation (Option H29); A56 Test Port 1 Option H29 Switch; A57 Test Port 2 Option H29 Switch; A58 Test Port 2 Option H29 Bridge - Keysight N5244A Service Manual

Theory of Operation

Noise Measurement Group Operation (Option H29)

Noise Measurement Group Operation (Option H29)
The noise measurement group measures the noise figure up to 26.5 GHz. Refer
to
Chapter
In this section the following assemblies are described:
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A56 Test Port 1 Option H29 Switch

The A56 bypass switch is placed in the Port 1 source path, allowing the source
signal to be switched between normal test mode configuration and internal
noise tuner configuration.

A57 Test Port 2 Option H29 Switch

The A57 bypass switch is placed in the Port 2 source path, allowing switching
between normal test mode configuration and noise figure measurement mode.
When the PNA-X is switched into noise figure measurement mode, the switch
allows both the source incident signal and the noise incident signal from the
DUT to simultaneously pass through to the A59 Noise Downconverter.

A58 Test Port 2 Option H29 Bridge

The A58 bridge is placed in the Port 2 source path. When the PNA-X is
switched into noise figure measurement mode, the noise incident signal from
the DUT passes through the A58 bridge before being sent to the A55 noise
downconverter. The A58 bridge also allows the source incident signal from A5
to pass through to test port 2 where the S-parameters and conversion gain
measurements can be done without any extra mechanical switching.

A59 Noise Downconverter

The A95 noise downconverter contains an input Low Noise Amplifier (LNA), an
RF Filter Bank, an LO Filter Bank, and a mixer. For 6 – 50 GHz signals, the LNA
provides the necessary gain to enable measurements on low noise and low
gain devices. The signals are routed through the RF Filter Bank where the noise
signal is filtered for third harmonic conversion rejection. The noise signals are
mixed with the LO synthesized signal to produce IF noise signals before being
sent to the A9 Noise Receiver board. For frequencies between 10 MHz – 3GHz,
5-36
Figure 5-9 on page 5-38
4.
A56 Test Port 1 Option H29 Switch
A57 Test Port 2 Option H29 Switch
A58 Test Port 2 Option H29 Bridge
A59 Noise Downconverter
A9 Noise Receiver Board
and the detailed block diagrams at the end of
Keysight N5244A/45A Service Guide