User`s guide

Chapter 3 3-3

Theory of Operation and Troubleshooting

Theory of Operation

Three-Port Test Set

The 8753ES Option H39 includes a three-port signal-separation test set

that routes signals from any two ports to the A and B receiver channel

samplers.Refer to Figure 3-12 on page 3-25and Figure 3-13 on page 3-26

for the component locations and RF paths.

Option H39 adds a third test port to the standard 8753ES test set. Three

test ports allow measurement applications for three-port devices with

the ability to make S-parameter measurements between any two test

ports. This option adds four additional solid-state switches, RF cabling to

redirect the RF source, and the A and B channel receiver inputs.

Port 1 is conﬁgured to operate as in a standard instrument, while Port 2

and Port 3 are switched in and out by one additional solid-state switch.

The A and B channel receiver inputs are redirected through a matrix of

three solid-state switches that connect directly to the coupled arm of

each test port coupler. Test ports are controlled by the internal TTL I/O

signals. Test ports are type-N.

A network analyzer with this option will have slightly degraded output

power levels, accuracy, and dynamic range.

NOTE With Option H39, test port bias can only be supplied to Port 1 from the

Port 1 bias connector on the rear panel. The Port 2 bias connector on the

rear panel is not connected.

Port 1 and Port 3 are the instrument’s default ports. On preset, or when

power is turned on, Port 1 and Port 3 are active.

Test Port Couplers

The analyzer’s test port couplers are used to separate signals incident to,

reﬂected from, and transmitted by the device under test. Each test port

coupler has a coupling factor of 16 dB.