Chapter 2
71
Block Diagrams
A17 RF Assembly
50 MHz Calibrator
The 50 MHz calibrator is adjusted to a final level of
−
32 dBm before the
signal goes through the RF input switch.The on-screen level in
spectrum mode should be
−
25 dBm, when calibrated. The on-screen
signal level reads
−
25 dBm because the 7 dB pad (AT1) is compensated
for through video shift further down in the system.
First Mixer
The first mixer converts incoming RF signals to a 321.4 MHz first IF by
mixing the input signal with a 321.4 to 4 GHz first local oscillator (LO).
This LO originates on the A19 synthesizer assembly. For input signals
less than or equal to 3678.6 MHz, the LO frequency is calculated as the
RF
+
321.4 MHz. For signals above 3678.6 MHz, the LO frequency is
calculated as the RF
−
321.4 MHz.
321.4 MHz Amplifiers
The amplifiers in the 321.4 MHz IF path are low
−
noise, high
dynamic
range.
Calibrator Switch
A 321.4 MHz calibrator signal is generated on the A17 RF assembly.
The cal switch selects between the main measurement path and the IF
calibration signal.
Image Filter
The image filter is centered at 321.4 MHz and is approximately 20 MHz
wide at the 3 dB bandwidth point.
Second Mixer
The second mixer converts the 321.4 MHz first IF to a 21.4 MHz second
IF by mixing the 321.4 MHz IF with the 300 MHz second LO. The
second LO originates on the A18 reference assembly.
Summary of Contents for E4406A VSA Series
Page 4: ...4 ...
Page 10: ...10 Contents ...
Page 11: ...11 1 Troubleshooting ...
Page 66: ...66 Chapter1 Troubleshooting How to Return Your Instrument for Service ...
Page 67: ...67 2 Block Diagrams ...
Page 119: ...Chapter 2 119 Block Diagrams Block Diagrams Block Diagrams ...
Page 120: ...120 Chapter2 Block Diagrams Block Diagrams ...
Page 122: ...122 Chapter2 Block Diagrams Block Diagrams ...
Page 124: ...124 Chapter2 Block Diagrams Block Diagrams ...
Page 125: ...125 3 Parts List ...
Page 164: ...164 Chapter3 Parts List Hardware ...
Page 165: ...165 4 Assembly Replacement ...
Page 169: ......
Page 170: ...170 Chapter4 Assembly Replacement Removal and Replacement Procedures ...
Page 227: ...Chapter 4 227 Assembly Replacement Front Frame Subassemblies Figure 4 39 Keypad Parts ...
Page 231: ...231 5 Post Repair Procedures ...
Page 262: ...262 Chapter5 Post Repair Procedures Automated Adjustments ...