A23 Test Set Motherboard - Keysight N5247B Series Service Manual

Theory of Operation
Synthesized Source Group Operation
ADC module (SPAM) board. The VCO output is also divided by two to produce
50 MHz reference signals for the A4, A15, and A17 13.5 GHz synthesizer
boards.
Rear-Panel Interconnects
10 MHz REF INPUT (s/n prefixes
<6021 only)
10 MHz REF OUTPUT (s/n prefixes
<6021 only)

A23 Test Set Motherboard

The A23 test set motherboard serves these functions:
— to act as an interface between the A21 CPU board and the auxiliary rear
— to provide ALC signals to the A25 HMA26.5.
— to route control signals to the signal separation group. Refer to
Rear Panel Interconnects
The A23 test set motherboard includes the following rear panel interconnects.
TEST SET I/O
HANDLER I/O
PWR I/O
Keysight N5247B Service Guide
A BNC connector that allows an external frequency reference signal to be used to
phase lock the analyzer for increased frequency accuracy.
The analyzer automatically enables the external frequency reference feature when
a signal is connected to this input. When the signal is removed, the analyzer
automatically switches back to its internal frequency reference.
A BNC connector that allows a 10 MHz reference signal, produced by the A14
frequency reference board, to be output for use in phase locking external test
equipment.
panel interconnects.
Separation Group Operation" on page 5-46
A DB-25 female connector that is used to control external test sets. The external test set bus
consists of 13 multiplexed address and data lines, three control lines, and an open-collector
interrupt line. Pin assignments are listed in
Up to 16 test sets may be "daisy-chained" on the bus at one time.
The Test Set I/O is not compatible with 8753 network analyzer test sets.
A rectangular 36-pin, female connector providing four independent parallel input/output
ports, nine control signal lines, one ground, and a power supply line. This connector has Type
2 output pin assignments as listed in
All signals are TTL-compatible. Data input/output ports consist of two 8-bit output ports (Port
A and Port B) and two 4-bit bidirectional ports (Port C and Port D).
Connector settings can be changed using SCPI and COM commands. The settings are not
accessible from the front panel.
A DB-9 female connector. Pin assignments are listed in
for more information.
Table 5-3 on page 5-30.
Table 5-4 on page 5-31.
Table 5-5 on page
"Signal
5-32.
5-29