BIRD SMK-3000 Series, Руководство пользователя

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RF Calibration Kit
2
RF Power Sensor Theory of Operation
The precision directional RF Power Sensor contains all necessary components to provide an accurate measurement
of forward and reflected power over the entire specified operating range. They contain the following functional
blocks:
RF measurement —
The RF Power Sensor uses directional coupler technology and square-law diode detection to
measure the RF signals. Excellent coupler directivity allows for accurate separation of forward and reflected power.
Square-law detection allows for accurate measurement of true average power for signals of all continuous wave
(CW) modulation types, including complex digital modulation.
Frequency sensing —
The RF Power Sensor contains a frequency measurement circuit that enables automatic
correction of measurements based on frequency specific calibration data that is stored in the sensor during factory
calibration.
Microprocessor control — The on-board microprocessor manages all functions of the sensor including data
collection, processing, calibration, and communication to external devices. The microprocessor and other circuitry
are powered from either of the communication interfaces (USB or serial).
Communication interface — The sensor supports two types of communication interfaces for accessing its
power measurements, USB and serial. Connection to the Bird 4421A RF Power Meter is available through the Sensor
Input (serial) interface. The 4421A RF Power Meter provides the simplest means of reading measurements from the
sensor. Connection to a computer is available through the USB interface, which enumerates as a USB-TMC device.
Measurements can be retrieved from the sensor using Standard Commands for Programmable Instruments (SCPI).
Some advanced features are also available through the USB interface, such as modifying the factory calibration.
4421A RF Power Meter
The 4421A RF Power Meter is used to display the measurements of the Bird RF Power Sensors in the RF Calibration
Kit. The 4421A is equipped with a touchscreen interface.
Figure 2 Bird 4421A RF Power Meter Assembly
One Sensor Operation — The 4421A RF Power Meter will display the RF power measurements of one RF Power
Sensor. The sensor may be connected to either of the Sensor connectors, see "4421A Controls and Indicators"
on page 6 .
Remote Operation —
The 4421A’s operation may be controlled from a remote computer/controller and RF
Sensor measurements from the sensor connected to the 4421A may be received on the remote computer. The
remote interfaces include RS-232 and Ethernet
.
Note: There are two protocols supported by the 4421A for remote operation, the legacy 4421 protocol
and the new SCPI protocol. Either command protocol may be used to remotely access a single sensor.
Optional Rack Mount Kit
A rack mounting kit is available for the 4421A, see Appendix 1 on page 29 .