338 Keysight N9038A MXE Service Guide
Analog & Digital IF
A3 Digital I.F. Assembly Description
A3 Digital IF Assembly Description
Data Acquisition
The 22.5 MHz IF comes from the A2 Analog IF assembly. The input level to
the A3 Digital IF assembly is
−
25 dBm. The IF input has a 25 MHz
bandwidth centered at 22.5 MHz. The analog circuitry leading to the ADC
converts the singled ended signal from the Analog IF to differential required
by the ADC. Finally, it couples in the dither signal. The ADC is a 14 bit
device sampling continuously at 90 Ms/Second.
Rear Panel Triggers
The board has two trigger inputs and two trigger outputs all used via a BNC
connector. The trigger inputs are used when an external device has a
trigger signal and the user wants to use that external trigger to trigger the
instrument. The trigger outputs are used to synchronize other pieces of test
equipment to the instrument. These outputs are configurable through the
Input/Output menu via the front panel of the instrument.
The trigger inputs each allow trigger levels to be set from
−
5 to +5 volts
using the control DAC. The circuits have relatively high input impedance.
The trigger outputs have 50
Ω
source impedance with TTL drive levels into
no load.
Control DAC
The control DAC is used to set trigger levels and the gain of the
reconstruction system. All three outputs can be adjusted from
−
2.5 to +2.5
volts.
Sample Rate Generator
The 10 MHz reference signal comes from the A16 Reference Assembly. This
signal is fairly high power at +10 dBm. The signal goes through a 10 MHz to
30 MHz tripler. A 0 to 5V 10 MHz square wave is generated. Capacitors
form a single-pole band pass filter to select the 3rd harmonic, 30 MHz.
The signal then passes through a 30 MHz to 90 MHz tripler. A 0 to 5V 30
MHz square wave is generated. Capacitors form a single-pole band pass
filter to select the 3rd harmonic, 90 MHz.
Noise Source Voltage Regulator
Various external noise sources can be connected to the rear panel of the
instrument. These noise sources require a very accurate 28 volt DC power
supply.
The 28 volt BNC output connector is used with the 346 series noise sources.
Refer to
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Страница 66: ...66 Keysight N9038A MXE Service Guide Boot Up and Initialization Potential Problems During Boot Process ...
Страница 130: ...130 Keysight N9038A MXE Service Guide Instrument Messages Condition Messages ...
Страница 216: ...216 Keysight N9038A MXE Service Guide RF Preselector Section RF Preselector Section Troubleshooting ...
Страница 268: ...268 Keysight N9038A MXE Service Guide L O Synthesizer A14 L O Synthesizer Assembly Troubleshooting ...
Страница 354: ...354 Keysight N9038A MXE Service Guide Analog Digital IF A3 Digital I F Troubleshooting ...
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Страница 436: ...Keysight N9038A MXE Service Guide 455 Service and Diagnostics Menus Service Menus Figure 16 5 Alignments Menu ...
Страница 500: ...Keysight N9038A MXE Service Guide 519 Replaceable Parts Hardware Figure 17 23 Front Frame Exploded View LED Backlight ...
Страница 504: ...Keysight N9038A MXE Service Guide 523 Replaceable Parts Hardware Figure 17 26 Front Frame Exploded View CCFL Backlight ...
Страница 589: ...608 Keysight N9038A MXE Service Guide Assembly Replacement Procedures Motherboard Assembly Figure 18 57 Bottom Screws ...
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Страница 643: ...662 Keysight N9038A MXE Service Guide Instrument Software Software Updates ...
Страница 741: ...760 Keysight N9038A MXE Service Guide Tests Intermittent Unsteady Drifting Disturbances ...