Rohde & Schwarz ZVB 14, Руководство по обслуживанию

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R&S ZVB Instrument Construction and Function Description
1145.1078.82 3.11 E-4
Description of the Block Diagram
The block diagrams shown in Fig. 3-1 to Fig. 3-9 apply to the R&S ZVB4, R&S ZVB8, R&S ZVB14 and
the R&S ZVB20 4 and 2 ports and to the R&S ZVB4 and R&S ZVB8 3 ports.
The R&S ZVB is a vector network analyzer covering 300 kHz to 4 GHz (R&S ZVB4), 300 kHz to 8 GHz
(R&S ZVB8),
10 MHz to 14 GHz (R&S ZVB14) or 10 MHz to 20 GHz (R&S ZVB20). All models are available in a 2-
port or in a 4-port version, 3-port versions are no longer available. The signals (including the LO signal
for the receiver) are generated using one or two synthesizer boards, according to the number of ports.
The signal processing path comprises a reflectometer board, an IF board, a network controller and a
processor section, comprising a Pentium-PC, I/O interface and graphics board. The instrument can be
expanded to handle future digital and analog requirements by retrofitting options.
The generator signal on R&S ZVB4/8 (300 kHz to 4 GHz or 300 kHz to 8 GHz) is generated on
synthesizer board 1, amplified in the generator section of the reflectometer board and then passes via
the bridge to the port (port1 to 4) and so to the DUT. The reference signal (Ref1 to 4) is split in the
bridge and fed to the receiver section (Receiver Ref1 to 4) on the reflectometer board.
The generator signal on R&S ZVB14/20 (10 MHz to 14 GHz or 10 MHz to 20 GHz) is generated on
synthesizer board 1, frequency multiplied, filtered and amplified in the generator section of the
reflectometer board and then passes via the coupler to the port (port1 to 4) and so to the DUT. The
reference signal (Ref1 to 4) is split in the coupler and fed to the receiver section (Receiver Ref1 to 4) on
the reflectometer board.
The signal reflected or transmitted by the DUT (Meas1 to 4) is fed to the port, coupled out in the bridge
or coupler unit and fed to the receiver section (Receiver Meas 1 to 4) on the reflectometer board.
The internal reference frequencies are generated on the frequency reference board. The 128-MHz
reference frequency is generated there as an internal device reference.
The following sections describe the various boards in greater detail.
Reflectometer R&S ZVB4/8
A reflectometer board comprising a bridge unit , a generator section (Generator) and a receiver
section (Receiver) are incorporated in every port (Port1 to 4). These three components are screwed
together to form a compact unit.
Bridge unit
The bridge unit is a resistive coupler which is used to separate the signal going to the DUT from the
signal coming from the DUT. The reference signal (= measure of the signal to the DUT) is also obtained
from the bridge unit. The reference signal provides a reference for relative measurements.
Generator
The generator contains three broadband amplifier stages which boost the signal coming from the
synthesizer to a level > 20 dBm. Limiter diodes protect the output stage from ESDs. A total of three
adjustable attenuators form the setting element to keep the output level constant and to attenuate it
electronically.