Agilent Technologies 83236B, Руководство по эксплуатации, Страница: 70 / 164

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Chapter 3, Programming the PCS Interface using GPIB Control
Overview of Programming Issues
Generator level
Setting
The PCS Interface’s generator path has a 0 to 70 dB attenuator with 10 dB steps
which provide coarse level settings of the RF generator. Fine level control is
provided by the 0.1 dB resolution of the Test Set’s DUPLEX OUT port.
The output signal level desired at the UUT’s port is set using an GPIB command.
When the PCS Interface’s generator level setting is received over GPIB, the CPU
of the PCS Interface automatically determines the appropriate generator path
attenuator setting, and computes a level which should be set at the Test Set’s
DUPLEX OUT port. This level is returned over GPIB and is then used by the
controlling software to set the Test Set’s RF generator level.
The automatic attenuator and level computations performed by the PCS
Interface’s CPU include two factors which are stored internally; a temperature (of
the PCS Interface) factor and an attenuation step accuracy factor. The temperature
correction factor is updated during the generator level temperature compensation
which is discussed later. The attenuator step accuracy correction factor is
established as part of the factory calibration. Both factors are also a function of
the current generator frequency. Therefore, the generator level setting should be
done
after setting the desired RF generator frequency.