Agilent Technologies HP 8719D Service Manual page 329

Figure 12-1. Simplified System Block Diagram
The built-in synthesized source of the analyzer generates a swept or CW
(continuous wave) signal in the following ranges:
HP 8719D
50
MHz to 13.5 GHz
The source output power is leveled by an internal ALC (automatic leveling
control) circuit, to a maximum level of +5 dBm (-10 dBm, HP 8722D) at the
front panel measurement ports. A portion of the source signal is routed to the R
sampler in the receiver, and fed back to the source for phase lock.
The signal separation devices separate the source signal into a reference path
and a test path. They provide attenuation for the source signal, RF path
switching to allow forward and reverse measurements, and external connections
for the DUT (device under test). The signal transmitted through or reflected
from the DUT goes to the receiver for comparison with the reference signal.
The receiver converts the source signal to a 4 kHz IF (intermediate frequency)
for signal processing, retaining both magnitude and phase characteristics. The
IF is converted to digital signals, which are processed into magnitude and phase
information. The processed and formatted data is finally routed to the display,
and to the HP-IB for remote operation.
12-2 Theory of Operation
HP 872013
50
MHz to 20 GHz
HP 8722D
50
MHz to 40 GHz