Installation guide

Troubleshooting
Block Descriptions for Option 501, 502, 503, 504
1-125
Analog Modulation
Block Description for All Options
Overview
Analog modulation for all options of signal generators is made from portions of the following:
• A18 Reference (Option 501, 502, 503, 504)
or A18 Reference (Option 501, 502, 503, 504 with Option 1E5)
or A18 Reference (Option UNJ or Option 506)
• A17 Synthesizer (Option 501, 502, 503, 504)
• A10 I/Q Multiplexer (Option 501, 502, 503, 504 or Option UNJ)
or A10 I/Q Multiplexer (Option 506)
• A13 Output (Option 501, 502, 503, 504 or Option UNJ)
or A13 Output (Option UNB)
• A7 Baseband Generator (Option 001 or Option 002)
• A23 Motherboard
• A15 Sampler (Option UNJ or Option 506)
• A21 YTO Driver (Option UNJ or Option 506)
The analog modulation block implements all analog modulations such as AM, FM, PM, and PULSE. The
signal generator can be modulated using internal or external signals:
• Internal modulating signals are supplied by an Internal Modulation Source Function Generator located
on the A23 Motherboard.
• External modulating signals can be ac or dc coupled through the EXT 1 and EXT 2 inputs.
The input impedance for the EXT 1 and EXT 2 inputs are 50 ohms nominal and are designed so that a
+1 Vp or a −1 Vp produces the indicated deviation or depth. When ac modulating signals are used and ac
coupled inputs are selected for FM/PM or AM, HI/LO annunciators will light if the peak input voltage
differs by more than ± 3% of 1 volt. This is accomplished using the over/under Mod detector.
I/Q and Burst signals from the Digital Modulation block can also be used as analog modulating signals. With
the exception of Burst Pulse, all modulation signals can be utilized to drive external equipment using the
LF OUTPUT port on the front panel.
Except for FM with PM, all modulation types can be simultaneously enabled. AM, FM, and PM can sum
simultaneous inputs from any two sources (INT, EXT 1, EXT 2, AUDIO 1, AUDIO 2) allowing for composite
modulating signals. Any given source (INT, EXT 1, EXT 2, AUDIO 1, AUDIO 2) can only be routed to one
activated modulation type.