Periodic permanent-magnet focusing is used with TWTs to:

1.	Periodic permanent-magnet focusing is used with TWTs to:
A.	Allow pulsed operation
B.	Improve electron bunching
C.	Avoid the bulk of an electromagnet
D.	Allow coupled-cavity operation at the highest frequencies
Answer» D. Allow coupled-cavity operation at the highest frequencies

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Periodic permanent-magnet focusing is used with TWTs to:

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