Anritsu 37 D Series, Руководство по обслуживанию, Страница: 39 / 190

Chapter 3
Theory of Operation
3-1
INTRODUCTION
This chapter provides a brief overview of the functional assemblies
and major parts that comprise a typical 37XXXD VNA system. It also
briefly describes the operation of each major assembly. Further details
of the ME7808B/C Broadband system are found in Appendix D.
3-2
SYSTEM OVERVIEW 37XXXD Vector Network Analyzers are ratio measurement systems
used to measure complex vector signal characteristics (real/imaginary,
magnitude/phase, etc) of devices and systems in the 40 MHz to 65 GHz
frequency range.
The VNA performs these measurements by sourcing a stimulus signal
to the Device Under Test (DUT) that is connected to the front panel
Port 1 and/or Port2 connectors. (See Figure 3-1 or 3-2 ). It simulta-
neously measures the DUT response, which consists of reflected and/or
transmitted (attenuated, or amplified) signals at the connectors of the
DUT. The reflected and/or transmitted signal(s), and a sample of the
stimulus signal, are down converted and then transformed into their
real and imaginary vector components. The resultant vector compo-
nents are measured and converted into digital information. This digi-
tal information is sent to the Main Processor PCB where the desired
S-parameter data is normalized and then presented to the user via the
front panel color display. The display information is also sent to the
rear panel VGA Out connector for use with an external VGA monitor.
The normalized measurement information is also sent to the rear
panel Printer Out connector for use with an external printer and/or
plotter.
A front panel keypad, a rotary knob, and an IBM compatible keyboard
interface provide user interaction with VNA Main Processor PCB.
The system is equipped with internal hard disk and floppy disk drives
and battery backed internal memories for storage and retrieval of data
and front panel setup information.
The VNA implements an IEEE 488.2 interface. This GPIB interface al-
lows an externally connected instrument controller to control the VNA
system in the “Remote-Only” mode. All VNA measurement and in-
put/output operations may be controlled remotely in this mode.
37XXXD MM 3-3