A2 Vector Module (N5172B/82B Only); A3 Rf Assembly (N5171B/72B/81B/82B Only) - Keysight N5171B EXG Service Manual

Troubleshooting
Overall Block Description

A2 Vector Module (N5172B/82B Only)

The A2 Vector Module, a self contained, fully enclosed, Arbitrary (ARB)
Baseband Generator (BBG) assembly, that supports digital modulation in the
N5172B/82B. It receives a 100 MHz clock signal and the main RF signals from
the A3 RF assembly when digital modulation is turned on. The RF signals are
I/Q modulated, band-pass filtered, amplified, and returned to the amplification
output stages of the A3 RF assembly. External I/Q input signals are also
applied via this assembly. The A2 Vector Module only has influence on the RF
carrier signal when the ARB BBG is turned on.

A3 RF Assembly (N5171B/72B/81B/82B only)

The A3 RF assembly combines circuitry traditionally found on individual,
interconnected assemblies such as Reference, Synthesizer, Fractional-N and
Output assemblies onto one PC assembly. In analog mode, this assembly is
completely autonomous in creating a RF carrier signal. Functioning with the
support hardware; i.e. A1 Power Supply, A5 CPU and the user interface via the
Front Panel, this one assembly is the warranted functionality and specifications
of the product. Analog mode bypasses other hardware, if installed; i.e. A2
Vector or A7 Real Time BBG assemblies.
Reference Circuitry
The reference circuitry uses either a high performance internal 10 MHz OCXO
(Oven) oscillator (MXG-B) or a 10 MHz VCTCXO oscillator (EXG-B). The
circuitry is designed to lock to an external reference frequency between 1 MHz
and 50 MHz, with a resolution less than 0.1 Hz when option 1ER is installed.
Without the flexible reference option (Option 1ER) the reference will only lock
to an external reference of 10 MHz.
The reference output signals are multiplied/divided to provide the following
signals:
— A 50 MHz reference signal to the synthesizer Frac-N and FM circuitry.
— A 500 MHz signal to the synthesizer PLL (only MXG-B)
— A 100 MHz clock signal to the A2 Vector Module.
— A 1 GHz LO signal to the heterodyne (HET) band mixer.
16 Keysight X-Series Signal Generators Service Guide