HP 85106D, Manual

Page: 113 / 244

4-20 HP 85106D mm-Wave System
Service and Troubleshooting
Check Unratioed Power Levels
The mixers illustrated in the test set block diagram of Figure 4-7 are
harmonic mixers. They mix the multiplied signal from the RF source and a
harmonic of the signal from the LO source to produce a 20 MHz IF output.
NOTE
All system instruments must be connected and averaging must be turned off
during this test.
To check all of the IF signals in the HP 85104A mm-Wave Test Sets, the a
2
and b
2
phase lock and drive paths must be redefined. If the configuration
disk has been loaded for the desired millimeter band, then the user
parameters are already defined. If manual entry is needed, press the
following keys on the HP 8510 to redefine a
2
:
PARAMETER [
MENU
]
{
USER 3 a2
}
{
REDEFINE PARAMETERS
}
{
DRIVE
} {
PORT 2
}
{
PHASE LOCK
} {
a2
}
{
REDEFINE DONE
}
To redefine b
2
, press:
{
USER 2 b2
}
{
REDEFINE PARAMETERS
}
{
DRIVE
} {
PORT 2
}
{
PHASE LOCK
} {
a2
}
{
REDEFINE DONE
}
NOTE
It is very important that you connect shorts to port 1 and port 2 on the test set
modules.