HP 70000 series, User Manual

Page: 371 / 447

Rear-P anel P orts
Figure B-9. HP 70900B local oscillator source , Rear View
100 MHz IN receives a 100 MHz external frequency reference to improve the stability of
the spectrum analyzer over time and temperature changes , and calibrate the
spectrum analyzer tuning with an external reference . The output of the
HP 70310A precision frequency reference Precision Frequency Reference
may be connected to the 100 MHz port. Y ou may connect other frequency
references .
SWEEP supplies the 0{10 volt sweep ramp .
TUNE + SP AN
OUT
is a voltage ramp with varying slope and dc level. The ramp normally is used
to control the tuning frequency of the HP 70900B local oscillator source ,
tracking-generator output, preselector lter , and external mixer interface
oscillator . HSWP IN/OUT is a 0 to +5 V square wave that is high during the
sweep and low between sweeps and between bands in multi-band sweeps .
T o disable the sweep , the port may be held low . EXT TRIG (external trigger)
receives an external signal that can determine when the spectrum analyzer
sweep begins .
300 MHz OUT supplies a phase-locking signal. Route the 300 MHz signal to other RF sections ,
the tracking-generator module , or external mixer interface module .
VIDEO IN receives the video signal from the IF module .
LO OUT supplies 3.0 to 6.6 GHz depending on the measurement range and the settings
of the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
LO OSC START and
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
LO OSC STOP keys .
HSWP IN/OUT has a TTL signal that is high any time the LO is sweeping. This port works
both as an output and input, allowing other modules in the system to interrupt
the sweep .
B-16 Input and Output P orts