HP 8530A, Руководство по эксплуатации и программированию, Страница: 56 / 439

Principles of Operation
Note
In hardware gating applications , the pulsed reference signal may not be suitable
for phase locking. In this case , you can use the other reference input for phase
locking. F or example , assume your pulsed reference is on input a1, you can use
a2 as the phase lock reference .
Any of the three remaining inputs can be used as test inputs .
Figure 2-3. Phase Lock Reference
The input selector sends one test signal and one reference signal to the synchronous detectors .
When these are measured, the input selector sends the other test/reference signals .
The synchronous detectors develop the real (x) and imaginary (y) parts of the test or
reference signal by comparing the input to an internally-generated 100 kHz sine wave . This
method practically eliminates drift, osets , and circularity errors as sources of measurement
uncertainty . Each x,y pair is sequentially converted to digital values which are sent to the
main microprocessor .
Digital Data Process Stages
Digital signal processing proceeds under the control of the receiver's rmware operating system
executed by the main microprocessor .
About the Main Microprocessor
The main microprocessor is a 32 bit Motorola 68020 microprocessor running at a clock speed of
16 MHz. The rmware operating system takes advantage of multi-tasking software architecture
and several distributed processors to provide very fast data acquisition and display update
speed.
System Overview 2-5