Hp 85104A Test Set Module; Introduction; Theory Of Operation; Warranty - HP 85106D Manual

5

Introduction

Theory Of Operation

Warranty

HP 85104A Test Set Module

This section documents the operation, troubleshooting techniques, and
replaceable parts of the HP 85104A test set module.
A pair of HP 85104A test set modules are used to make either reflection,
transmission, or S-parameter measurements at mm-wave frequencies, in
conjunction with an HP 85105A mm-wave controller. The mm-wave
controller routes the LO and RF signals from RF and LO sources to the test
set modules. Switching from port 1 to port 2 is also performed by the
mm-wave controller. The test set modules separate the incident from the
reflected RF signal and then down convert those signals to a 20 MHz IF
frequency.
Refer to the HP 85104A block diagrams (Figure 5-7 on page 5-23 through
Figure 5-10 on page 5-29) while reading the following description. The RF
is received from the mm-wave controller and input to the source module
block of the test set module. The RF is then multiplied six times in the case
of W-band (2 times for R-band, 8 times for Q-band, 8 times for U-band and
4 times for V-band). This multiplied RF signal then passes through a
coupler/detector (only in V and W bands) where the signal is sampled for
use in an ALC loop. The RF continues through an isolator and a dual
directional coupler. A portion of the incident signal is coupled off, passed
through an isolator, and into a harmonic mixer, A11. The signal received at
the test port (either transmitted from another test set module or reflected
from a device under test) is coupled off, passed through an isolator, and into
a harmonic mixer, A12. The 2-8 GHz LO signal is input from the source
through the mm-wave controller. The signal is then divided and input to the
harmonic mixer. In the case of W-band, the sixteenth harmonic of the LO
mixes with the RF so that a 20 MHz IF frequency is output. The LO
harmonic product must be 20 MHz higher in frequency than the RF signal.
The IF frequencies (incident and reflected) are then output to the mm-wave
controller for further processing. The mixing harmonics for other bands are;
R-band: 8, Q-band: 10, U-band: 10, and V-band: 14. The isolators in the test
set modules are used to keep reflections from the dual directional coupler,
A8, from interfering with the source, and to keep reflections from the
mixers, All and A12, from interfering with the incident and reflected RF
signals.
Refer to Chapter 1, "Getting Started" in this manual for warranty
information about the HP 85104A.
HP 85106D mm-Wave System 5-1