Service Modes Menu - Agilent Technologies 8719ET Service Manual

8719ET/20ET/22ET
8719ES/20ES/22ES
RF Network Analyzers

Service Modes Menu

To access this menu, press
SERVICE MODES
FRACN TUNE on OFF
SRC ADJUST MENU
If the instrument displays the PHASE LOCK CAL FAILED message, use the
NOTE
DAC NUM XXX BAND
relationship between DAC numbers and frequency varies between
instruments. The DAC numbers, provided in the description, and frequencies
are guidelines only.
•
SOURCE TUNE OFF
modes.
•
DAC NUM XXX BAND
and source assemblies. These keys allow entry of digital data directly
into the DAC on the A11 phase lock assembly. When in this mode:
— Instrument does not attempt to phase lock.
— Residual FM increases.
•
DAC NUM LOW BAND
the range of 3650 through 4095 to generate test port output frequencies
from 50 MHz to 1.1 GHz.
•
DAC NUM MID BAND
DAC numbers in the range of 2900 through 4095 to generate test port
output frequencies from 2.3 GHz to 4.9 GHz.
Service Guide
SERVICE MENU
System
allows you to control and monitor various circuits for
troubleshooting.
(SM1) tests the A13 and A14 fractional-N circuits. It allows you
to directly control and monitor the output frequency of the
fractional-N synthesizer (60 MHz to 240 MHz).
Set the instrument to CW sweep mode and then set
FRACN TUNE ON. Change frequencies with the front
panel keys or knob. The output of the A14 assembly can be
checked at A14J1 HI OUT (in high band) or A14J2 LO
OUT (in low band) with an oscilloscope, a frequency
counter, or a spectrum analyzer. Signal jumps and changes
in shape at 20 MHz and 30 MHz when tuning up in
frequency, and at 29.2 MHz and 15 MHz when tuning
down, are due to switching of the digital divider. This
mode can be used with the SRC TUNE mode as described
in Chapter 7 , "Source Troubleshooting."
accesses the functions that allow you to adjust the source:
keys of the Source Adjustment Menu. The
(SM2D) disables the source frequency tune
tests the pretune functions of the phase lock
(SM2L) allows you to enter DAC numbers in
(SM2M) (8722ET/ES only) allows you to enter
Service Key Menus and Error Messages
Service Menu - Service Features
.
SERVICE MODES
10- 17