Counter (Sg-G); X-Y Plotter (Sg-H); Power Supplies (Sg-I) - HP 3585A Service Manual

Model 3585A
plotter output functions and local oscillator control is handled through the I/O portion of
the processor. Devices that are not controlled via the I/O are ROM, RAM, Counter and
HP-lB.
The keyboard is constantly monitored by the processor via the I/O. Pressing a switch on the
keyboard generates a priority interrupt to the processor and the keyboard is serviced as re­
quired.
6·6. Display (SG·o)
The Display section of the instrument has its own processor and is interfaced to the central
processor via the I/O . The display processor controls all display operations as well as display
and plotter output functions.
A master clock is generated as part of the Display section. This clock is used by the central
processor, HP-IB interface, and the display processor.
6· 7. Tracking Generator (SG·E)
The Tracking Generator's primary purpose is to generate a sweeping 0 to 40 MHz signal that
tracks the sweeping LO signal. The Tracking Generator output is found on the instrument
front panel.
The Tracking Generator section also controls the signal that goes into the calibrator circuitry
of the RF /IF section. The signal to the calibrator is either a 10 MHz reference signal or the
Tracking Generator output.
6·8. Hp·IB (SG·F)
The instrument central processor is interfaced to the "outside world" via the HP-IB section.
The HP-IB section has its own processor and is directly connected to the instrument main
processor via the IOD bus.
An HP-IB connector is provided at the rear panel of the instrument. This connector is used
to connect the instrument to other instruments and controllers which have HP-IB (IEEE
488) capability.
6·9. Counter (SG·G)
The Counter is a 24-bit counter that measures the frequency of the signal that is producing
the response on which the marker is positioned. Counter input is from the IF section and the
10 MHz reference. Counter output is via bus to the processor.
6· 1 0. X· Y Plotter (SG·H)
The X-Y Plotter section provides plotter outputs on the rear panel of the instrument. Digital
data from the Display section is digital-to-analog (D/ A) converted, filtered, ,and made
available at the plotter output connectors.
6·1 1 . Power Supplies (SG·I)
The Power Supply section generates all dc voltages and controls their distribution. The dc
voltages generated are + 7. 7V, + 5V, + 1 2V, + 1 8V, and - 1 8V .
Circuit Functional Descriptions
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